# ent

id: cord-001371-wf0vonkn
type: ORG
entity:
  Simultaneous Detection and Differentiation of Highly Virulent and Classical Chinese Type Isolation of PRRSV by Real Time RT PCR


id: cord-005376-tzmettky
type: DNA
entity:
  5 GTGGATGCTTTCACGGAGTTC 3 and 5 CACACTTAATTAACGTTTTTTTTTTTTTTTTTTTT TTTTTTTTTTTTTTTTTTTTTTTAATTTCGGCCGTGT GGTTC 3


id: cord-029839-jxqi9exm
type: GGP
entity:
  interleukin 2 IL 2 interleukin 4 IL 4 interferon alpha IFN α interferon gamma IFN γ tumor necrosis factor alpha TNF α


id: cord-281676-yy5etfek
type: CELL_TYPE
entity:
  natural killer NK cells CD3 CD4 CD8 40 T helper cells CD3 CD4 CD8 cytotoxic T lymphocytes CTLs CD3 CD4 CD8 CD4CD8 double positive T cells CD3 CD4 CD8


id: cord-281676-yy5etfek
type: CELL_TYPE
entity:
  T helper memory cells 41 42 T cells CD8 TcR1N4 T regulatory cells CD4 CD25 Foxp3 CD172 myeloid cells CD4 CD25 Foxp3 activated T helper cells dendritic cells


id: cord-001134-8ljgxnhf
type: DNA
entity:
  PCR 12 13 14 15 16 17 18 19 20 21 SYBR Green based PCR 11 22 23 24 RT PCR 1 virus isolation 1 immunohistochemistry 1


id: cord-262347-ejhz9rra
type: ORG
entity:
  Industry Study Assessment of the Economic Impact of Porcine Reproductive and Respiratory Syndrome Virus


id: cord-299751-2drhoz70
type: ORG
entity:
  the Research Institute for Biological Safety Problems Science Committee Ministry of Education and Science


id: cord-281309-c9y7m5do
type: CELL_TYPE
entity:
  lung tracheobronchial lymph node trachea thymus heart tonsil spleen iliac lymph node mesenteric lymph nodes ileum bone marrow kidneys liver inguinal lymph node cerebrum brainstem cerebellum and ventral midbrain


id: cord-259771-653opx0h
type: ORG
entity:
  Public Health Service Policy United States Department of Agriculture Regulations the National Research Council s Guide for the Care and Use of Laboratory Animals


id: cord-275403-g4rohhtt
type: DNA
entity:
  adapter primers 5Ј 30 ApaI 5Ј ACTAG GGCCCTTAACAAAAAAAAAAAAAAAAAAA 3Ј UTR NdeI 5Ј ACTAGCATATGGCACTAGTGATTCCGGAAT 5Ј 65 ApaI 5Ј


id: cord-275403-g4rohhtt
type: GGP
entity:
  PRRSV 14 nsp 9 10 and 11 described below After optimal conditions were determined soluble recombinant proteins


id: cord-275403-g4rohhtt
type: ORG
entity:
  Functional Properties of the Predicted Helicase of Porcine Reproductive and Respiratory Syndrome Virus


id: cord-310771-tnwfp1je
type: TAXON
entity:
  transmissible gastroenteritis virus TGEV porcine respiratory coronavirus PRCV Chlamydophila Brucella


id: cord-289152-w5ynbewh
type: PROTEIN
entity:
  pro inflammatory cytokines chemokines adhesion molecules matrix metalloproteinases MMPs cyclooxygenase 2 COX2


id: cord-289152-w5ynbewh
type: PROTEIN
entity:
  anti NF nB p65 Santa Cruz Biotechnology Santa Cruz CA anti InBa Cell Signaling Beverly MA anti InBh Santa Cruz Biotechnology Santa Cruz CA anti InBq Santa Cruz Biotechnology Santa Cruz CA anti rabbit IgG HRP Amersham Biosciences Piscataway NJ


id: cord-289152-w5ynbewh
type: PROTEIN
entity:
  kinases TGF beta activated kinase 1 mitogenactivated kinase extracellular signal regulated kinase kinase 1


id: cord-289152-w5ynbewh
type: GGP
entity:
  EBV gp350 activate NF nB signaling pathway through binding to CD4 and CD21 Bossis et al 2002 D Addario et al 1999 Sugano et al 1997 However it is unlikely that NF nB activation by PRRSV


id: cord-301563-s0ypy2hf
type: DNA
entity:
  retinoic acid inducible gene I RIG I TANK binding kinase 1 TBK1 TNF receptor associated factor 6 TRAF6


id: cord-003841-7uaj9hmx
type: ORG
entity:
  CXCL 8 Secretion Induction of Apoptosis and Promotion of Efferocytosis Anti Inflammatory Benefits of


id: cord-260840-tudl9k1g
type: GGP
entity:
  PRRSV I 06 3 5 2 99 AE 1 26 C 4 5 4 82 AE 1 47 C 5 5 6 00 AE 0 92 B 5 5 6 25 AE 0 02 B B3 PRRSV I 92 4 5 4 52 AE 1 14 5 5 7 47 AE 0 12 5 5 7 43 AE 0 14 5 5 7 28 AE 0 09 B3 PRRSV I 06 4 4 3 84 AE 0 63 3 4 4 57 AE 1 53 4 4 6 12 AE 1 33 4 4 7 13 AE 0 44 Different superscripts A B C D


id: cord-312787-j7ye7ed5
type: TAXON
entity:
  Transmissible gastroenteritis virus Swine influenza virus encephalomyocarditis virus S hyodysenteriae sarcoptic


id: cord-332049-geh9aaf5
type: PROTEIN
entity:
  PRRS VR 2332 specific primers MLV F1 5 0 GCAGCTCCCATCTACAGCTGATT 3 0 and MLV R1 5 0 AGACAATGTGAGTCA AAACGGGAAAGAT 3 0


id: cord-332049-geh9aaf5
type: PROTEIN
entity:
  Mycoplasma hyopneumoniae DAKO M hyo ELISA Oxoid APP Cypress Diagnostics swine influenza virus SIV IDEXX transmissible gastroenteritis virus TGEV SVANOVA


id: cord-004151-9815ikzg
type: PROTEIN
entity:
  nsp1 membrane rearrangement nsp2 and nsp3 replicative endonuclease nsp11 major virulence factors nsp3 8


id: cord-261160-g92zhv19
type: DISEASE
entity:
  kidney bladder heart aorta liver intestines stomach testes ovaries nasal turbinates and salivary glands


id: cord-010094-t0y3t9v3
type: CHEMICAL
entity:
  polyglycerol 4 aminophenylboronic acid hydrochloride benzoxazine PEG diamine 3 ethoxypropylamine curcumin


id: cord-003962-lg6gvgwt
type: PROTEIN
entity:
  PLP2 protein 1 µM Ub AMC Boston biochem U 550 and 1 reaction buffer 137 mM NaCl 2 7 mM KCl 4 3 mM Na2HPO4 1 4 mM KH2PO4 and 2 mM DTT


id: cord-003962-lg6gvgwt
type: WORK_OF_ART
entity:
  The Ubiquitin Proteasome Pathway Is Required for Processing the Nf Kappa B1 Precursor Protein and the Activation of Nf Kappa B


id: cord-003962-lg6gvgwt
type: ORG
entity:
  the Porcine Reproductive and Respiratory Syndrome Virus Viral Ovarian Tumor Domain Protease Specificity


id: cord-009443-0vis4bwi
type: ORG
entity:
  Arteriviridae Porcine Reproductive and Respiratory Syndrome Virus PRRSV Pathogenesis and Interaction


id: cord-009443-0vis4bwi
type: WORK_OF_ART
entity:
  A Synthetic Porcine Reproductive and Respiratory Syndrome Virus Strain Confers Unprecedented Levels of Heterologous Protection DNA


id: cord-342276-zrsnahi7
type: CELL_LINE
entity:
  China Grant No Porcine reproductive and respiratory syndrome The challenge of PRRS immunology Lactate dehydrogenase


id: cord-270688-g703hhm4
type: GGP
entity:
  Microb Pathog DOI 10 1016 j micpath 2020 104385 sha 15f4c085d5bb0a04c95643acc8dffebaf76ec6a3 doc_id 270688 cord_uid g703hhm4


id: cord-288669-46tkedw7
type: DNA
entity:
  A12062G mutation E KO Fwd 5 GAATTGAAATGAAgTGGGGTCTATAC 3 nucleotide positions 12 049 to 12 074 and E KO Rev 5 GTATA GACCCCAcTTCATTTCAATTC 3 nucleotide positions 12 049 to 12 074


id: cord-288669-46tkedw7
type: DNA
entity:
  positive sense genomic RNA negative sense genomic RNA positive sense subgenomic mRNA7 or negative sense subgenomic mRNA7 PCR


id: cord-288669-46tkedw7
type: GGP
entity:
  small hydrophobic nonstructural proteins of Japanese encephalitis virus Hepatitis C virus E1 protein


id: cord-283689-dzin12qb
type: PROTEIN
entity:
  anti GAPDH mouse anti ATG5 Alexa Fluor 488 conjugated anti rabbit IgG Alexa Fluor 488 conjugated anti mouse IgG


id: cord-255828-jrqdyfbg
type: DNA
entity:
  GP4 http mobyle pasteur fr cgi bin portal py forms toppred Claros and von Heijne 1994 and the GPI anchor attachment signal http gpi unibe ch Fankhauser and Mäser 2005 Eisenhaber et al 1998


id: cord-266199-smlq11y9
type: DISEASE
entity:
  influenza A virus in swine Assessing production parameters and economic impact of swine influenza PRRS


id: cord-269560-vq462fh2
type: TAXON
entity:
  virus Actinobacillus pleuropneumoniae Bordetella bronchiseptica Brachyspira hyodysenteriae Brachyspira pilosicoli


id: cord-275413-e2rhioty
type: GGP
entity:
  fetuses 1 2 3 12 4 9 4 11 4 13 in Fig 1 The mechanism for fetal pathology remains unclear but the results suggest that the source pathology is likely result of the infection of tissues on the maternal side


id: cord-285746-ndrja7os
type: CHEMICAL
entity:
  Caesalpinia sappan Linn Garcinia mangostana Linn Houttuynia cordata Perilla frutescens Clinacanthus nutans Phyllanthus emblica and Tiliacora triandra


id: cord-285746-ndrja7os
type: CHEMICAL
entity:
  2 2 diphenyl 1picrylhydrazyl DPPH and 2 57 0 16 mg ml n 2 2azino bis 3 ethylbenzothiazo line 6 sulfonic acid diammonium salt ABTS


id: cord-264598-2u8bm2fz
type: CELL_TYPE
entity:
  pulmonary macrophage subpopulations pulmonary alveolar macrophages PAMs pulmonary intravascular macrophage PIMs


id: cord-264598-2u8bm2fz
type: GGP
entity:
  Díaz I Revilla C Mateu E Domínguez J Martín Valls G Barranco I Pallarés F J Carrasco L Gómez Laguna J title Activation of pro and anti


id: cord-312208-8ydh6jev
type: DNA
entity:
  PRRSV genes 5 0 viral polymerase ORFs 1a 1b virion associated proteins GP2 ORF 2 GP3 ORF 3 GP4 ORF 4 GP5 ORF 5 M ORF 6 N ORF 7 3 0


id: cord-298131-zolwjl9u
type: PROTEIN
entity:
  apolipoprotein B48 receptor APOB48R apolipoprotein E APOE low density lipoprotein B LDLB phosphatidylinositol 3 kinase catalytic subunit type 3 PIK3C3 Figure 3B


id: cord-298131-zolwjl9u
type: DISEASE
entity:
  acute respiratory syndrome coronavirus life cycle Hepatitis C virus hijacks host lipid metabolism Common


id: cord-335706-lopcb77c
type: CHEMICAL
entity:
  carboxy terminal beta strand of the porcine reproductive and respiratory syndrome virus nucleocapsid protein The 2b


id: cord-321471-gev5xq3a
type: RNA
entity:
  nonsegmented negative stranded RNA viruses 30 Unexpectedly our investigation with the PI3K specific inhibitor LY294002 showed that the PI3K Akt


id: cord-328935-mn8r972x
type: DNA
entity:
  influenza virus hemagglutinin gene Equine influenza virus infections an update Probiotic bacteria enhance murine


id: cord-328935-mn8r972x
type: DISEASE
entity:
  diseases of the respiratory reproductive and gastrointestinal tracts of domestic animals and poultry


id: cord-344953-gtg12hiu
type: ORG
entity:
  the Federation of Animal Science Societies Guide for the Care and Use of Agricultural Animals in Research and Teaching the USDA Animal Welfare Act and Animal Welfare Regulations


id: cord-324495-0pee1i3o
type: DNA
entity:
  3 0 UTR 5 0 AATTTCGGCCGCATGGTTTTCGCCAATTAAATCTT ACCCCCACACGGTCGC 3 0 or porcine 16S rRNA 5 0 G CGGTTGCACCATTTGGGTGTCCTG 3 0 The blot


id: cord-306948-wkisfz1m
type: PROTEIN
entity:
  nuclear export signal sequences Replication competent recombinant porcine reproductive and respiratory syndrome PRRS viruses expressing indicator proteins


id: cord-306948-wkisfz1m
type: WORK_OF_ART
entity:
  cDNA templates Interplay between interferon mediated innate immunity and porcine reproductive and respiratory syndrome virus Crystal structure of porcine reproductive and respiratory syndrome virus leader protease nsp1 alpha


id: cord-306948-wkisfz1m
type: CHEMICAL
entity:
  carboxy terminal beta strand of the porcine reproductive and respiratory syndrome virus nucleocapsid protein Full length sequence


id: cord-345516-fgn7rps3
type: PROTEIN
entity:
  DFFAlike effector C CIDEC tumor suppressor candidate 5 TUSC5 protein phosphatase 1 regulatory inhibitor subunit 1A PPP1R1A C type lectin domain family 4 member G


id: cord-345516-fgn7rps3
type: PROTEIN
entity:
  transforming growth factor beta TGFB1 activity beta 1 adrenergic receptor ADRB1 Solute carrier family 2


id: cord-351881-qea4b0i5
type: DNA
entity:
  Olot 91 strain GenBank Accession Number AGW23409 was synthesized by GenScript Piscataway For generation


id: cord-353703-u86ggw11
type: WORK_OF_ART
entity:
  The PERK Arm of the Unfolded Protein Response Negatively Regulates Transmissible Gastroenteritis Virus Replication by


# bib

id: cord-000403-vzbh457k
author: Zhang, Weijun
date: 2011-05-30
txt: ./txt/cord-000403-vzbh457k.txt
cache: ./cache/cord-000403-vzbh457k.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3126774/
doi: 10.1186/1743-422x-8-263
summary:
  Twenty-seven nanopeptides derived from the matrix (M) protein of porcine reproductive and respiratory syndrome virus (PRRSV) were screened for their ability to elicit a recall interferon-γ (IFN-γ) response from the splenocytes of BALB/c mice following DNA vaccination and a booster vaccination with recombinant vaccinia virus rWR-PRRSV-M. We screened peptides derived from the PRRSV M protein for their ability to induce interferon (IFN)-γ in splenocytes harvested from BALB/ c mice following DNA vaccination and a booster vaccination with recombinant vaccinia virus expressing M protein. In contrast, control mice vaccinated with pVAX1-only or PBS-only did not show significant increases in M protein-specific antibody titers after the booster vaccination with rWR-PRRSV-M (P > 0.05, Additional file 5, Fig. S5 ). Specific increases in the number of cells producing IFN-γ following stimulation with the peptides "K 93 FITSRCRL" and "F 57 GYMTFVHF" was observed by day 3 after the booster vaccination with rWR-PRRSV-M (Figure 1 and 2) .

title:
  Identification of CD8(+ )cytotoxic T lymphocyte epitopes from porcine reproductive and respiratory syndrome virus matrix protein in BALB/c mice

abstract:
  Twenty-seven nanopeptides derived from the matrix (M) protein of porcine reproductive and respiratory syndrome virus (PRRSV) were screened for their ability to elicit a recall interferon-γ (IFN-γ) response from the splenocytes of BALB/c mice following DNA vaccination and a booster vaccination with recombinant vaccinia virus rWR-PRRSV-M. We identified two peptides (amino acid residues K(93)FITSRCRL and F(57)GYMTFVHF) as CD8(+ )cytotoxic T lymphocyte (CTL) epitopes. These peptides elicited significant numbers of IFN-γ secreting cells, compared with other M nonapeptides and one irrelevant nonapeptide. Bioinformatics analysis showed that the former is an H-2K(d)-restricted CTL epitope, and the latter is an H-2D(d)-restricted CTL epitope. Multiple amino acid sequence alignment among different PRRSV M sequences submitted to GenBank indicated that these two CTL epitopes are strongly conserved, and they should therefore be considered for further research on the mechanisms of cellular immune responses to PRRSV.


id: cord-001134-8ljgxnhf
author: Lin, Chao-Nan
date: 2013-09-12
txt: ./txt/cord-001134-8ljgxnhf.txt
cache: ./cache/cord-001134-8ljgxnhf.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3847877/
doi: 10.1186/1746-6148-9-181
summary:
  title: Comparison of viremia of type II porcine reproductive and respiratory syndrome virus in naturally infected pigs by zip nucleic acid probe-based real-time PCR In this study, we developed a sensitive and specific zip nucleic acid probe-based real-time PCR assay to evaluate the viremia of natural PRRSV-infected pigs in Taiwan. CONCLUSIONS: ZNA probe-based real-time PCR can be a useful tool to diagnose symptomatic and asymptomatic PRRSV-infected pigs. ZNA probe-based real-time PCR amplification and the limit of detection Tenfold serial plasmid dilutions (10 1 to 10 6 copies/μl) were tested and used to construct the standard curve by plotting the logarithm of the plasmid copy number against the measured quantification cycles (Cq) values. However, this is first study to report the viral load using serum samples in asymptomatic PRRSV-infected pigs using ZNA probebased real-time PCR. Development of a onestep real-time quantitative PCR assay based on primer-probe energy transfer for the detection of porcine reproductive and respiratory syndrome virus

title:
  Comparison of viremia of type II porcine reproductive and respiratory syndrome virus in naturally infected pigs by zip nucleic acid probe-based real-time PCR

abstract:
  BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is a RNA virus with high genetic variation. This virus causes significant economic losses in most pig-producing countries. The clinical presentation of PRRSV ranges from asymptomatic to devastating. In this study, we developed a sensitive and specific zip nucleic acid probe-based real-time PCR assay to evaluate the viremia of natural PRRSV-infected pigs in Taiwan. Serum samples were collected from 577 pigs aged 5–12 weeks. These include 444 clinically healthy pigs and 133 symptomatic pigs were confirmed to have porcine respiratory disease complex (PRDC). RESULTS: Viremia was quantified in 79 of the 444 (17.8%) clinically healthy pigs and in 112 of the 133 (84.2%) PRDC cases. Viremias were significantly more common in pigs with PRDC compared with the clinically healthy pigs (P <0.0001). These results suggest that a high viral load is a major feature of PRRSV-affected pigs. CONCLUSIONS: ZNA probe-based real-time PCR can be a useful tool to diagnose symptomatic and asymptomatic PRRSV-infected pigs. The presence of this marker in a sample of animals with high PRRSV loads (>10(4.2) PRRSV genomes/μl of serum) seems to indicate that it correlates with the presence of PRDC in pigs.


id: cord-001236-cgiok0ce
author: Binjawadagi, Basavaraj
date: 2014-03-24
txt: ./txt/cord-001236-cgiok0ce.txt
cache: ./cache/cord-001236-cgiok0ce.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3969340/
doi: 10.2147/ijn.s59924
summary:
  title: An innovative approach to induce cross-protective immunity against porcine reproductive and respiratory syndrome virus in the lungs of pigs through adjuvanted nanotechnology-based vaccination Therefore, we attempted to strengthen the immunogenicity of inactivated/killed PRRSV vaccine antigens (KAg), especially in the pig respiratory system, through: 1) entrapping the KAg in biodegradable poly(lactic-co-glycolic acid) nanoparticles (NP-KAg); 2) coupling the NP-KAg with a potent mucosal adjuvant, whole cell lysate of Mycobacterium tuberculosis (M. 32 In adjuvanted NP-KAgvaccinated pigs, increased avidity of virus-specific IgA was detected in both BAL fluid (both low and high doses) and lung homogenate (only low dose) samples compared to other tested groups (Figure 2A-C) . Adjuvanted poly(lactic-co-glycolic) acid nanoparticle-entrapped inactivated porcine reproductive and respiratory syndrome virus vaccine elicits cross-protective immune response in pigs Intranasal delivery of whole cell lysate of Mycobacterium tuberculosis induces protective immune responses to a modified live porcine reproductive and respiratory syndrome virus vaccine in pigs

title:
  An innovative approach to induce cross-protective immunity against porcine reproductive and respiratory syndrome virus in the lungs of pigs through adjuvanted nanotechnology-based vaccination

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) is an economically devastating respiratory disease of pigs. The disease is caused by the PRRS virus (PRRSV), an Arterivirus which is a highly mutating RNA virus. Widely used modified live PRRSV vaccines have failed to prevent PRRS outbreaks and reinfections; moreover, safety of the live virus vaccines is questionable. Though poorly immunogenic, inactivated PRRSV vaccine is safe. The PRRSV infects primarily the lung macrophages. Therefore, we attempted to strengthen the immunogenicity of inactivated/killed PRRSV vaccine antigens (KAg), especially in the pig respiratory system, through: 1) entrapping the KAg in biodegradable poly(lactic-co-glycolic acid) nanoparticles (NP-KAg); 2) coupling the NP-KAg with a potent mucosal adjuvant, whole cell lysate of Mycobacterium tuberculosis (M. tb WCL); and 3) delivering the vaccine formulation twice intranasally to growing pigs. We have previously shown that a single dose of NP-KAg partially cleared the challenged heterologous PRRSV. Recently, we reported that NP-KAg coupled with unentrapped M. tb WCL significantly cleared the viremia of challenged heterologous PRRSV. Since PRRSV is primarily a lung disease, our goal in this study was to investigate lung viral load and various immune correlates of protection at the lung mucosal surfaces and its parenchyma in vaccinated heterologous PRRSV-challenged pigs. Our results indicated that out of five different vaccine-adjuvant formulations, the combination of NP-KAg and unentrapped M. tb WCL significantly cleared detectable replicating infective PRRSV with a tenfold reduction in viral RNA load in the lungs, associated with substantially reduced gross and microscopic lung pathology. Immunologically, strong humoral (enhanced virus neutralization titers by high avidity antibodies) and cell-mediated immune responses (augmented population of interferon-γ secreting CD4(+) and CD8(+) lymphocytes and reduced secretion of immunosuppressive cytokines) in the lungs were observed. In conclusion, combination of NP-KAg and soluble M. tb WCL elicits broadly cross-protective anti-PRRSV immunity in the pig respiratory system.


id: cord-001371-wf0vonkn
author: Xiao, Shuqi
date: 2014-06-12
txt: ./txt/cord-001371-wf0vonkn.txt
cache: ./cache/cord-001371-wf0vonkn.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119655/
doi: 10.1155/2014/809656
summary:
  The real-time RT-PCR developed based on SYBR Green and TaqMan probe could be used for simultaneous detection and differentiation of HP-PRRSV and PRRSV in China, which will benefit much the PRRS control and research. In this research, the real-time RT-PCR for simultaneous detection and differentiation of HP-PRRSV and PRRSV by using both SYBR Green and TaqMan probe was developed and validated. Our results showed that real-time PCR using both SYBR Green I and TaqMan probe could be used to simultaneously detect and differentiate HP-PRRSV and PRRSV in China. The real-time PCR developed based on SYBR Green and TaqMan probe could be used for simultaneous detection and differentiation of HP-PRRSV and PRRSV in China, which provided two alternative diagnostic assays in diverse PRRSV epidemiological circumstances. Simultaneous detection and genotyping of porcine reproductive and respiratory syndrome virus (PRRSV) by real-time RT-PCR and amplicon melting curve analysis using SYBR Green

title:
  Simultaneous Detection and Differentiation of Highly Virulent and Classical Chinese-Type Isolation of PRRSV by Real-Time RT-PCR

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) is a leading disease in pig industry worldwide and can result in serious economic losses each year. The PRRS epidemic situation in China has been very complicated since the unprecedented large-scale highly pathogenic PRRS (HP-PRRS) outbreaks in 2006. And now the HP-PRRS virus (HP-PRRSV) and classical North American type PRRSV strains have coexisted in China. Rapid differential detection of the two strains of PRRSV is very important for effective PRRS control. The real-time RT-PCR for simultaneous detection and differentiation of HP-PRRSV and PRRSV by using both SYBR Green and TaqMan probes was developed and validated. Both assays can be used for rapid detection and strain-specific identification of HP-PRRSV and PRRSV. However, the TaqMan probe method had the highest detection rate whereas the conventional RT-PCR was the lowest. The real-time RT-PCR developed based on SYBR Green and TaqMan probe could be used for simultaneous detection and differentiation of HP-PRRSV and PRRSV in China, which will benefit much the PRRS control and research.


id: cord-002087-o8kffjw0
author: Shi, Xibao
date: 2016-06-06
txt: ./txt/cord-002087-o8kffjw0.txt
cache: ./cache/cord-002087-o8kffjw0.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4895886/
doi: 10.1186/s12917-016-0717-5
summary:
  title: Nonstructural protein 11 (nsp11) of porcine reproductive and respiratory syndrome virus (PRRSV) promotes PRRSV infection in MARC-145 cells RESULTS: Here, we firstly explored the effect of over-expression of nsp11 on PRRSV infection and found that over-expression of nsp11 enhanced the PRRSV titers while the small interfering RNA (siRNAs) specifically targeting nsp11 could reduce the PRRSV titers in MARC-145 cells. Abbreviations EAV, equine arteritis virus; GAPDH, Glyceraldehyde-3-phosphate dehydrogenase; GFP-nsp11, pcDNA 3.1-GFP-nsp11; MHV, mouse hepatitis virus; MOI, multiplicity of infection; NLRP3, NLR family pyrin domain-containing 3; nsp11, nonstructural protein 11; ORF, open reading frame; PRRSV, porcine reproductive and respiratory syndrome virus ; PVDF, polyvinylidene difluoride; qRT-PCR, quantitative real-time RT-PCR; RNAi, RNA interference; siRNA, small interfering RNA; TCID50, 50 % tissue culture infected dose Identification of two auto-cleavage products of nonstructural protein 1 (nsp1) in porcine reproductive and respiratory syndrome virus infected cells: nsp1 function as interferon antagonist

title:
  Nonstructural protein 11 (nsp11) of porcine reproductive and respiratory syndrome virus (PRRSV) promotes PRRSV infection in MARC-145 cells

abstract:
  BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) induces one of most important devastating disease of swine worldwide, and the current methods poorly control it. Previous studies have indicated that the nonstructural protein 11 (nsp11) of PRRSV may be an important protein for the immune escape of PRRSV. RESULTS: Here, we firstly explored the effect of over-expression of nsp11 on PRRSV infection and found that over-expression of nsp11 enhanced the PRRSV titers while the small interfering RNA (siRNAs) specifically targeting nsp11 could reduce the PRRSV titers in MARC-145 cells. CONCLUSION: In conclusion, PRRSV nsp11 promotes PRRSV infection in MARC-145 cells and siRNAs targeting nsp11 may be a potential therapeutic strategy to control PRRSV in future.


id: cord-002589-xq3iq8ai
author: Frossard, Jean-Pierre
date: 2017-06-09
txt: ./txt/cord-002589-xq3iq8ai.txt
cache: ./cache/cord-002589-xq3iq8ai.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5490802/
doi: 10.3390/v9060110
summary:
  To follow up these studies, we report here on (1) the investigation of PRRSV active infection (RNA in tonsil) using the same 2013 abattoir survey sample-set and (2) an analysis of the correlation of PRRSV and HEV infection in these pigs, which could be of significance for the control of both diseases and in informing farming practices for reducing HEV in the food chain. The phylogenetic trees (Figure 1 ) illustrate the genetic diversity of the ORF5 genes from the 23 samples in this study in comparison to the vaccine virus licensed in the UK at the time and 48 published reference sequences representing the different genotypes and subtypes ( Figure 1A ) and in more detail, in the context of 431 previously sequenced viruses specifically from UK pigs between 1991 and 2014 (unpublished data) ( Figure 1B ).

title:
  UK Pigs at the Time of Slaughter: Investigation into the Correlation of Infection with PRRSV and HEV

abstract:
  Hepatitis E virus (HEV) and porcine reproductive and respiratory syndrome virus (PRRSV) and are both globally prevalent in the pig population. While HEV does not cause clinical disease in pigs, its zoonotic potential has raised concerns in the food safety sector. PRRS has become endemic in the United Kingdom (UK) since its introduction in 1991, and continues to cause considerable economic losses to the swine industry. A better understanding of the current prevalence and diversity of PRRSV and HEV in the UK, and their potential association, is needed to assess risks and target control measures appropriately. This study used plasma, tonsil, and cecal content samples previously collected from pigs in 14 abattoirs in England and Northern Ireland to study the prevalence of several pathogens including PRRSV and HEV. The diversity of PRRSV strains detected in these samples was analyzed by sequencing open reading frame 5 (ORF5), revealing no substantial difference in PRRSV strains from these clinically unaffected pigs relative to those from clinical cases of disease in the UK. Despite the potential immuno-modulatory effect of PRRSV infection, previously demonstrated to affect Salmonella and HEV shedding profiles, no significant association was found between positive PRRSV status and positive HEV status.


id: cord-002590-24o2viv3
title: Mechanisms of Adaptive Immunity to Porcine Reproductive and Respiratory Syndrome Virus
author: Rahe, Michael C.
date: 2017-06-13
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5490824/
doi: 10.3390/v9060148
abstract:
  The adaptive immune response is necessary for the development of protective immunity against infectious diseases. Porcine reproductive and respiratory syndrome virus (PRRSV), a genetically heterogeneous and rapidly evolving RNA virus, is the most burdensome pathogen of swine health and wellbeing worldwide. Viral infection induces antigen-specific immunity that ultimately clears the infection. However, the resulting immune memory, induced by virulent or attenuated vaccine viruses, is inconsistently protective against diverse viral strains. The immunological mechanisms by which primary and memory protection are generated and used are not well understood. Here, we summarize current knowledge regarding cellular and humoral components of the adaptive immune response to PRRSV infection that mediate primary and memory immune protection against viruses.


id: cord-003144-nqkw5v3w
author: Qu, Zehui
date: 2017-11-24
txt: ./txt/cord-003144-nqkw5v3w.txt
cache: ./cache/cord-003144-nqkw5v3w.txt
extension: .txt
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url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6084361/
doi: 10.1002/pmic.201700101
summary:
  title: Label‐Free Quantitative Proteomic Analysis of Differentially Expressed Membrane Proteins of Pulmonary Alveolar Macrophages Infected with Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus and Its Attenuated Strain Significant differences exist between the highly pathogenic (HP) porcine reproductive and respiratory syndrome virus (PRRSV) and its attenuated pathogenic (AP) strain in the ability to infect host cells. This is the first attempt to explore the differential characteristics between HP‐PRRSV and its attenuated PRRSV infected PAMs focusing on membrane proteins which will be of great help to further understand the different infective mechanisms of HP‐PRRSV and AP‐PRRSV. Differentially expressed proteins between control and HP-PRRSV-infected cells (Con/HP) and the www.advancedsciencenews.com www.proteomics-journal.com p <0.01 and ratio >2 or <0.5 indicated quantitative difference between two groups. By analyzing detected proteins in HP-infected, AP-PRRSV-infected, and control group, proteins related to the immune response or virus replication were identified that may elucidate unique pathways used by different virulent PRRSVs for cell entry, virus replication, and immune escape mechanisms.

title:
  Label‐Free Quantitative Proteomic Analysis of Differentially Expressed Membrane Proteins of Pulmonary Alveolar Macrophages Infected with Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus and Its Attenuated Strain

abstract:
  Significant differences exist between the highly pathogenic (HP) porcine reproductive and respiratory syndrome virus (PRRSV) and its attenuated pathogenic (AP) strain in the ability to infect host cells. The mechanisms by which different virulent strains invade host cells remain relatively unknown. In this study, pulmonary alveolar macrophages (PAMs) are infected with HP‐PRRSV (HuN4) and AP‐PRRSV (HuN4‐F112) for 24 h, then harvested and subjected to label‐free quantitative MS. A total of 2849 proteins are identified, including 95 that are differentially expressed. Among them, 26 proteins are located on the membrane. The most differentially expressed proteins are involved in response to stimulus, metabolic process, and immune system process, which mainly have the function of binding and catalytic activity. Cluster of differentiation CD163, vimentin (VIM), and nmII as well as detected proteins are assessed together by string analysis, which elucidated a potentially different infection mechanism. According to the function annotations, PRRSV with different virulence may mainly differ in immunology, inflammation, immune evasion as well as cell apoptosis. This is the first attempt to explore the differential characteristics between HP‐PRRSV and its attenuated PRRSV infected PAMs focusing on membrane proteins which will be of great help to further understand the different infective mechanisms of HP‐PRRSV and AP‐PRRSV.


id: cord-003492-rodqdtfj
title: Key Gaps in the Knowledge of the Porcine Respiratory Reproductive Syndrome Virus (PRRSV)
author: Montaner-Tarbes, Sergio
date: 2019-02-20
txt: ./txt/cord-003492-rodqdtfj.txt
cache: ./cache/cord-003492-rodqdtfj.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391865/
doi: 10.3389/fvets.2019.00038
summary:
  PRRSV is a complex disease and several gaps in the knowledge of its economic impact, biology and evolution, genetic polymorphism, mechanism of viral infections, elicitation of protective immune responses and novel control strategies, have been reviewed here (Box 1). Nonstructural proteins nsp2TF and nsp2N of porcine reproductive and respiratory syndrome virus (PRRSV) play important roles in suppressing host innate immune responses Immune responses in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV) Immunodominant epitopes in nsp2 of porcine reproductive and respiratory syndrome virus are dispensable for replication, but play an important role in modulation of the host immune response Nonstructural protein 11 (nsp11) of porcine reproductive and respiratory syndrome virus (PRRSV) promotes PRRSV infection in MARC-145 cells Immune response to ORF5a protein immunization is not protective against porcine reproductive and respiratory syndrome virus infection

abstract:
  The porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important swine diseases in the world. It is causing an enormous economic burden due to reproductive failure in sows and a complex respiratory syndrome in pigs of all ages, with mortality varying from 2 to 100% in the most extreme cases of emergent highly pathogenic strains. PRRSV displays complex interactions with the immune system and a high mutation rate, making the development, and implementation of control strategies a major challenge. In this review, the biology of the virus will be addressed focusing on newly discovered functions of non-structural proteins and novel dissemination mechanisms. Secondly, the role of different cell types and viral proteins will be reviewed in natural and vaccine-induced immune response together with the role of different immune evasion mechanisms focusing on those gaps of knowledge that are critical to generate more efficacious vaccines. Finally, novel strategies for antigen discovery and vaccine development will be discussed, in particular the use of exosomes (extracellular vesicles of endocytic origin). As nanocarriers of lipids, proteins and nucleic acids, exosomes have potential effects on cell activation, modulation of immune responses and antigen presentation. Thus, representing a novel vaccination approach against this devastating disease.


id: cord-003841-7uaj9hmx
author: Desmonts de Lamache, D.
date: 2019-08-23
txt: ./txt/cord-003841-7uaj9hmx.txt
cache: ./cache/cord-003841-7uaj9hmx.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6707645/
doi: 10.1371/journal.pone.0221560
summary:
  The findings indicate that tulathromycin, in the absence of a direct anti-viral effect, is able to restore the phagocytic function and to attenuate the pro-inflammatory phenotype of PRRSV-infected monocyte-derived porcine macrophages. However, Immuno-modulating properties of Tulathromycin in PRRSV-infected porcine monocyte-derived macrophages PRRSV-induced IL-10 inhibition was abolished when the cells were pre-treated with tulathromycin at 2 and 12 hours post infection (Fig 6) . Another set of experiments assessed the effects of PRRSV, and of tulathromycin, on the nonopsonized and opsonized phagocytic functions of MDMs. PRRSV infection significantly Immuno-modulating properties of Tulathromycin in PRRSV-infected porcine monocyte-derived macrophages inhibited both phagocytic functions of the cells (Figs 10 and 11 ). The findings indicate that TUL inhibits PRRSV-induced inflammatory responses in porcine monocyte-derived macrophages and protects against the phagocytic impairment caused by the virus, in the absence of any direct anti-viral effects.

title:
  Immuno-modulating properties of Tulathromycin in porcine monocyte-derived macrophages infected with porcine reproductive and respiratory syndrome virus

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) is a positive-stranded RNA virus that grows in macrophages and causes acute pneumonia in pigs. PRRSV causes devastating losses to the porcine industry. However, due to its high antigenic variability and poorly understood immunopathogenesis, there is currently no effective vaccine or treatment to control PRRSV infection. The common occurrence of PRRSV infection with bacterial infections as well as its inflammatory-driven pathobiology raises the question of the value of antibiotics with immunomodulating properties for the treatment of the disease it causes. The macrolide antibiotic Tulathromycin (TUL) has been found to exhibit potent anti-inflammatory and immunomodulating properties in cattle and pigs. The aim of this study was to characterize the anti-viral and immunomodulating properties of TUL in PRRSV-infected porcine macrophages. Our findings indicate that blood monocyte-derived macrophages are readily infected by PRRSV and can be used as an effective cellular model to study PRRSV pathogenesis. TUL did not change intracellular or extracellular viral titers, not did it alter viral receptors (CD163 and CD169) expression on porcine macrophages. In contrast, TUL exhibited potent immunomodulating properties, which therefore occurred in the absence of any direct antiviral effects against PRRSV. TUL had an additive effect with PRRSV on the induction of macrophage apoptosis, and inhibited virus-induced necrosis. TUL significantly attenuated PRRSV-induced macrophage pro-inflammatory signaling (CXCL-8 and mitochondrial ROS production) and prevented PRRSV inhibition of non-opsonized and opsonized phagocytic function. Together, these data demonstrate that TUL inhibits PRRSV-induced inflammatory responses in porcine macrophages and protects against the phagocytic impairment caused by the virus. Research in live pigs is warranted to assess the potential clinical benefits of this antibiotic in the context of virally induced inflammation and tissue injury.


id: cord-003962-lg6gvgwt
author: Zhou, Shaochuan
date: 2019-09-26
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6832237/
doi: 10.3390/v11100896
title:
  Characterizing the PRRSV nsp2 Deubiquitinase Reveals Dispensability of Cis-Activity for Replication and a Link of nsp2 to Inflammation Induction

abstract:
  The papain-like cysteine protease 2 (PLP2) within the N-terminus of the porcine reproductive and respiratory syndrome virus (PRRSV) nsp2 replicase protein specifies a deubiquitinating enzyme (DUB), but its biochemical properties and the role in infection have remained poorly defined. By using in vitro assays, we found that the purified PLP2 could efficiently cleave K63 and K48 linked polyubiquitin chains Ub3-7 in vitro although displaying a differential activity in converting the respective ubiquitin dimers to monomer. The subsequent mutagenesis analyses revealed that the requirement for PLP2 DUB activity surprisingly resembled that for cis-cleavage activity, as several mutations (e.g., D91R, D85R, etc.) that largely ablated the DUB function also blocked the cis- but not trans-proteolytic cleavage of nsp2/3 polyprotein. Moreover, the analyses identified key mutations that could differentiate DUB from PLP2 cis- and trans-cleavage activities. Further reverse genetics analyses revealed the following findings: (i) mutations that largely blocked the DUB activity were all lethal to the virus, (ii) a point mutation T88G that selectively blocked the cis-cleavage activity of PLP2 did not affect viral viability in cell culture, and (iii) an E90Q mutation that did not affect either of the PLP2 activities led to rescue of WT-like virus but displayed significantly reduced ability to induce TNF-α production. Our findings support the possibility that the PLP2 DUB activity, but not cis-cleavage activity, is essential for PRRSV replication. The data also establish a strong link of nsp2 to pro-inflammatory cytokine induction during infection that operates in a manner independent of PLP2 DUB activity.


id: cord-003970-3e58229u
title: Temporal Dynamics of Co-circulating Lineages of Porcine Reproductive and Respiratory Syndrome Virus
author: Paploski, Igor Adolfo Dexheimer
date: 2019-11-01
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6839445/
doi: 10.3389/fmicb.2019.02486
abstract:
  Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is the most important endemic pathogen in the U.S. swine industry. Despite control efforts involving improved biosecurity and different vaccination protocols, the virus continues to circulate and evolve. One of the foremost challenges in its control is high levels of genetic and antigenic diversity. Here, we quantify the co-circulation, emergence and sequential turnover of multiple PRRSV lineages in a single swine-producing region in the United States over a span of 9 years (2009–2017). By classifying over 4,000 PRRSV sequences (open-reading frame 5) into phylogenetic lineages and sub-lineages, we document the ongoing diversification and temporal dynamics of the PRRSV population, including the rapid emergence of a novel sub-lineage that appeared to be absent globally pre-2008. In addition, lineage 9 was the most prevalent lineage from 2009 to 2010, but its occurrence fell to 0.5% of all sequences identified per year after 2014, coinciding with the emergence or re-emergence of lineage 1 as the dominant lineage. The sequential dominance of different lineages, as well as three different sub-lineages within lineage 1, is consistent with the immune-mediated selection hypothesis for the sequential turnover in the dominant lineage. As host populations build immunity through natural infection or vaccination toward the most common variant, this dominant (sub-) lineage may be replaced by an emerging variant to which the population is more susceptible. An analysis of patterns of non- synonymous and synonymous mutations revealed evidence of positive selection on immunologically important regions of the genome, further supporting the potential that immune-mediated selection shapes the evolutionary and epidemiological dynamics for this virus. This has important implications for patterns of emergence and re-emergence of genetic variants of PRRSV that have negative impacts on the swine industry. Constant surveillance on PRRSV occurrence is crucial to a better understanding of the epidemiological and evolutionary dynamics of co-circulating viral lineages. Further studies utilizing whole genome sequencing and exploring the extent of cross-immunity between heterologous PRRS viruses could shed further light on PRRSV immunological response and aid in developing strategies that might be able to diminish disease impact.


id: cord-004151-9815ikzg
author: Pan, Xiaocheng
date: 2020-01-08
txt: ./txt/cord-004151-9815ikzg.txt
cache: ./cache/cord-004151-9815ikzg.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6960135/
doi: 10.3389/fimmu.2019.02995
summary:
  To investigate CTL epitope applications in swine, SLA-1(*)1502-restricted peptide epitopes matching porcine reproductive and respiratory syndrome virus (PRRSV) strains were explored by crystallography, biochemistry, and the specific pathogen-free (SPF) swine experiments. Next, the potential SLA-1(*)1502-restricted peptide epitopes matching four typical genetic PRRSV strains were identified based on the peptide-binding motif of SLA-1(*)1502 determined by structural analysis and alanine scanning of the NSP9-TMP9 peptide. In an attempt to identify anti-PRRSV CTL epitopes in this study, first, predicted peptide epitopes derived from PRRSV were synthesized, and a trimolecular complex, the structure of the epitope from PRRSV-NSP9 (TMPPGFELY, termed NSP9-TMP9)-bound SLA-1 * 1502 (pSLA-1 * 1502), was solved. The purified complex (44 kDa) of pSLA-1 * 1502 with the NSP9-TMP9 peptide (amino acid sequence TMPPGFELY, derived from residues 198-206 of the PRRSV non-structural protein) was dialyzed against crystallization buffer (20 mM Tris-HCl pH 8.0, 50 mM NaCl) and concentrated to 12 mg/mL.

title:
  Illumination of PRRSV Cytotoxic T Lymphocyte Epitopes by the Three-Dimensional Structure and Peptidome of Swine Lymphocyte Antigen Class I (SLA-I)

abstract:
  To investigate CTL epitope applications in swine, SLA-1(*)1502-restricted peptide epitopes matching porcine reproductive and respiratory syndrome virus (PRRSV) strains were explored by crystallography, biochemistry, and the specific pathogen-free (SPF) swine experiments. First, nine predicted PRRSV peptides were tested by assembly of the peptide-SLA-1(*)1502 (pSLA-1(*)1502) complexes, and the crystal structure of the SLA-1(*)1502 complex with one peptide (NSP9-TMP9) was determined. The NSP9-TMP9 peptide conformation presented by pSLA-1(*)1502 is different from that of the peptides presented by the known pSLA-1(*)0401 and pSLA-3(*)hs0202 complexes. Two consecutive Pro residues make the turn between P3 and P4 of NSP9-TMP9 much sharper. The D pocket of pSLA-1(*)1502 is unique and is important for peptide binding. Next, the potential SLA-1(*)1502-restricted peptide epitopes matching four typical genetic PRRSV strains were identified based on the peptide-binding motif of SLA-1(*)1502 determined by structural analysis and alanine scanning of the NSP9-TMP9 peptide. The tetrameric complex of SLA-1(*)1502 and NSP9-TMP9 was constructed and examined. Finally, taking NSP9-TMP9 as an example, the CTL immunogenicity of the identified PRRSV peptide epitope was evaluated. The SPF swine expressing the SLA-1(*)1502 alleles were divided into three groups: modified live vaccine (MLV), MLV+NSP9-TMP9, and the blank control group. NSP9-TMP9 was determined as a PRRSV CTL epitope with strong immunogenicity by flow cytometry and IFN-γ expression. Our study developed an integrated approach to identify SLA-I-restricted CTL epitopes from various important viruses and is helpful in designing and applying effective peptide-based vaccines for swine.


id: cord-004477-qu2o2iu1
title: Editorial: Porcine Anti-Viral Immunity
author: Vlasova, Anastasia N.
date: 2020-03-06
txt: ./txt/cord-004477-qu2o2iu1.txt
cache: ./cache/cord-004477-qu2o2iu1.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7067899/
doi: 10.3389/fimmu.2020.00399
abstract: nan
summary:
  Immediately following viral infection, neonatal survival depends on innate immunity and passive protection by lactogenic immune factors such as pathogen-specific antibodies, until an adaptive immune response can develop. Wide-spread porcine reproductive and respiratory syndrome virus (PRRSV) and swine influenza virus (SIV) represent major health challenges in the large US swine production systems and possibly worldwide. In introducing the topic of anti-viral immunity, we emphasize the genetic diversity of viruses, the virus life cycle and the pathology that viral infection can cause. A more tedious procedure is to use only parts of the virus as the vaccine (subunit vaccines) that target the immune response to those viral epitopes that elicit VN antibodies. A second approach to vaccine development is use of live attenuated virus that has been genetically modified or cell culture adapted and cannot produce a disease in the host but can still replicate.


id: cord-004754-5596p4ma
author: Duan, X.
date: 2014-04-06
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7086874/
doi: 10.1007/s007050050256
title:
  Effects of origin and state of differentiation and activation of monocytes/macrophages on their susceptibility to porcine reproductive and respiratory syndrome virus (PRRSV)

abstract:
  In this study, the susceptibility of porcine peripheral blood monocytes (BMo), peritoneal macrophages (PMφ) and alveolar macrophages (AMφ) to PRRSV was examined. To test the effect of differentiation and activation on their susceptibility, AMφ and BMo were aged, cultivated in either adhesion or suspension and treated with bacterial lipopolysaccharide (LPS) and phorbol myristate acetate (PMA). It was found that freshly isolated PMφ and BMo were non-permissive to PRRSV. PMφ remained refractory but a few BMo became susceptible after 1 day cultivation. AMφ were permissive with a significant increase of their susceptibility after one day cultivation. In a binding assay, it was demonstrated that the attachment of biotinylated PRRSV to AMf is much more efficient than to PMφ and BMo. Two monoclonal antibodies (Mabs) 41D3 and 41D5 which block PRRSV infection of AMφ and are directed against a candidate receptor for PRRSV only reacted with the cell membrane of AMφ. PMA treatment of AMφ blocked PRRSV replication in the cells in a dose-dependent manner. The blocking effect of PMA decreased after 9 h continuous pre-treatment and diminished after 24 h continuous pre-treatment. PMA treatment did not affect the binding of PRRSV and MAb 41D3 and 41D5 to AMφ. Direct or indirect treatment of AMφ and BMo with LPS or cultivation in suspension did not significantly affect their susceptibility. These results provide clear evidence that PRRSV has a strongly restricted tropism for only some sub-populations of porcine monocytes/macrophages and that some specific states of differentiation and activation of monocytes/macrophages considerably affect their susceptibility.


id: cord-004838-cdas57cx
author: Morozov, I.
date: 1995
txt: ./txt/cord-004838-cdas57cx.txt
cache: ./cache/cord-004838-cdas57cx.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7087238/
doi: 10.1007/bf01322758
summary:
  title: Sequence analysis of open reading frames (ORFs) 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus The sequence of ORFs 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus (PRRSV), ATCC VR2385, was determined by analysis of a cDNA λ library. No overlap was found between ORFs 4 and 5, and instead there was a 10 bp sequence which separated these two ORFs. The nucleic acid homology with corresponding ORFs of the European PRRSV isolate Lelystad virus (LV) was 65% for ORF 2, 64% for ORF 3 and 66% for ORF 4. Cloning, expression, and sequence analysis of the ORF 4 gene of porcine reproductive and respiratory syndrome virus MN-lb Molecular cloning and nucleotide sequencing of the 3''-terminal genomic RNA of porcine reproductive and respiratory syndrome virus

title:
  Sequence analysis of open reading frames (ORFs) 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus

abstract:
  The sequence of ORFs 2 to 4 of a U.S. isolate of porcine reproductive and respiratory syndrome virus (PRRSV), ATCC VR2385, was determined by analysis of a cDNA λ library. The cDNA clones containing PRRSV specific sequences were selected using a VR2385 ORF 4 specific PCR probe and sequenced. The ORFs 2, 3 and 4 overlapped each other and encoded polypeptides with predicted M(r) of 29.5 kDa (ORF 2), 28.7 kDa (ORF 3) and 19.5 kDa (ORF 4), respectively. No overlap was found between ORFs 4 and 5, and instead there was a 10 bp sequence which separated these two ORFs. The nucleic acid homology with corresponding ORFs of the European PRRSV isolate Lelystad virus (LV) was 65% for ORF 2, 64% for ORF 3 and 66% for ORF 4. Comparison of the ORF 4 sequences of VR2385 with that of another U.S. isolate MN-1b revealed only 86% amino acid sequence homology and the presence of deletions in the ORF 4 of MN-1b. Our results further strengthen the observation that there is sequence variation between US and European PRRSV isolates.


id: cord-005372-7x8ro8p2
author: Jiménez, Luisa Fernanda Mancipe
date: 2014-08-08
txt: ./txt/cord-005372-7x8ro8p2.txt
cache: ./cache/cord-005372-7x8ro8p2.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7091121/
doi: 10.1007/s12250-014-3471-5
summary:
  PRDC is caused by a combination of viral and bacterial agents, such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and Porcine circovirus 2 (PCV2). Our findings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh. Swine infl uenza is an acute, highly contagious respiratory disease resulting from infection with type A infl uenza virus, a member of the Orthomyxoviridae family. PRDC results from a combination of viral and bacterial agents, including porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and porcine circovirus type 2 (PCV2) (Kim J, et al., 2003) . The main goal of the current research was to generate surveillance, epidemiological, antigenic as well as phylogenetic data to ascertain the presence of swine influenza (H1N1) pandemic virus and determine its association with PRDC (PRRSV, Myh, APP and PCV2) in sows from production farms in Colombia.

title:
  Association of swine influenza H1N1 pandemic virus (SIV-H1N1p) with porcine respiratory disease complex in sows from commercial pig farms in Colombia

abstract:
  Porcine respiratory disease complex (PRDC) is a serious health problem that mainly affects growing and finishing pigs. PRDC is caused by a combination of viral and bacterial agents, such as porcine reproductive and respiratory syndrome virus (PRRSV), swine influenza virus (SIV), Mycoplasma hyopneumoniae (Myh), Actinobacillus pleuropneumoniae (APP), Pasteurella multocida and Porcine circovirus 2 (PCV2). To characterize the specific role of swine influenza virus in PRDC presentation in Colombia, 11 farms from three major production regions in Colombia were examined in this study. Nasal swabs, bronchial lavage and lung tissue samples were obtained from animals displaying symptoms compatible with SIV. Isolation of SIV was performed in 9-day embryonated chicken eggs or Madin-Darby Canine Kidney (MDCK) cells. Positive isolates, identified via the hemagglutination inhibition test, were further analyzed using PCR. Overall, 7 of the 11 farms were positive for SIV. Notably, sequencing of the gene encoding the hemagglutinin (HA) protein led to grouping of strains into circulating viruses identified during the human outbreak of 2009, classified as pandemic H1N1-2009. Serum samples from 198 gilts and multiparous sows between 2008 and 2009 were obtained to determine antibody presence of APP, Myh, PCV2 and PRRSV in both SIV-H1N1p-negative and -positive farms, but higher levels were recorded for SIV-H1N1p-positive farms. Odds ratio (OR) and P values revealed statistically significant differences (p<0.05) in PRDC presentation in gilts and multiparous sows of farms positive for SIV-H1N1p. Our findings indicate that positive farms have increased risk of PRDC presentation, in particular, PCV2, APP and Myh.


id: cord-005376-tzmettky
author: Lee, Jung-Ah
date: 2014-03-29
txt: ./txt/cord-005376-tzmettky.txt
cache: ./cache/cord-005376-tzmettky.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7091204/
doi: 10.1007/s12275-014-4074-4
summary:
  The K418 chimeric virus of porcine reproductive and respiratory syndrome virus (PRRSV) was engineered by replacing the genomic region containing structure protein genes of an infectious clone of PRRSV, FL12, with the same region obtained from a Korean dominant field strain, LMY. In previous studies, diverse chimera viruses of PRRSV have been generated using RG technology to manipulate viral genomes to determine the viral protein involved in the pathogenicity of field strains in pigs (Kwon et al., 2006; Zhou et al., 2012; Ni et al., 2013) . In this study, a chimeric virus was constructed using an infectious clone of PRRSV containing genomes of the FL12 strain and a Korean dominant field strain, LMY. To generate customized vaccine candidate, the genomic region of established PRRSV infectious clone encoding structure proteins that play a critical role in the virus neutralizing response were replaced with the same genomic region from a Korean dominant field strain of PRRSV.

title:
  Development of a chimeric strain of porcine reproductive and respiratory syndrome virus with an infectious clone and a Korean dominant field strain

abstract:
  The K418 chimeric virus of porcine reproductive and respiratory syndrome virus (PRRSV) was engineered by replacing the genomic region containing structure protein genes of an infectious clone of PRRSV, FL12, with the same region obtained from a Korean dominant field strain, LMY. The K418 reached 10(6) TCID(50)/ml of viral titer with similar growth kinetics to those of parental strains and had a cross-reactive neutralizing antibody response to field serum from the entire country. The chimeric clone pK418 can be used as a practical tool for further studying the molecular characteristics of PRRSV proteins through genetic manipulation. Furthermore, successful construction of the K418 will allow for the development of customized vaccine candidates against PRRSV, which has evolved rapidly in Korea.


id: cord-005378-u2bbgn8k
title: Overview: Replication of porcine reproductive and respiratory syndrome virus
author: Yun, Sang-Im
date: 2013-12-19
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7091224/
doi: 10.1007/s12275-013-3431-z
abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV), an arterivirus that causes significant losses in the pig industry, is one of the most important animal pathogens of global significance. Since the discovery of the virus, significant progress has been made in understanding its epidemiology and transmission, but no adequate control measures are yet available to eliminate infection with this pathogen. The genome replication of PRRSV is required to reproduce, within a few hours of infection, the millions of progeny virions that establish, disseminate, and maintain infection. Replication of the viral RNA genome is a multistep process involving a replication complex that is formed not only from components of viral and cellular origin but also from the viral genomic RNA template; this replication complex is embedded within particular virus-induced membrane vesicles. PRRSV RNA replication is directed by at least 14 replicase proteins that have both common enzymatic activities, including viral RNA polymerase, and also unusual and poorly understood RNA-processing functions. In this review, we summarize our current understanding of PRRSV replication, which is important for developing a successful strategy for the prevention and control of this pathogen.


id: cord-007476-wu9tuvy9
author: Katz, Jonathan B.
date: 2000-03-10
txt: ./txt/cord-007476-wu9tuvy9.txt
cache: ./cache/cord-007476-wu9tuvy9.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7117291/
doi: 10.1016/0378-1135(94)00113-b
summary:
  title: Antigenic differences between European and American isolates of porcine reproductive and respiratory syndrome virus (PRRSV) are encoded by the carboxyterminal portion of viral open reading frame 3 Antigenic differences between European and American isolates of porcine reproductive and respiratory syndrome virus (PRRSV) were revealed by serologic analysis of a recombinant protein derived from PRRSV open reading frame 3 (ORF 3). Sera from rabbits inoculated with BP03-P failed to neutralize both the European (Lelystad) and American (ATCC VR-2332) reference isolates of PRRSV and did not react by IPMA with PRRSV-infected cell cultures. Sera from rabbits inoculated with BPO3-P failed to neutralize both the European (Lelystad) and American ( ATCC VR-2332) reference isolates of PRRSV and did not react by IPMA with PRRSV-infected cell cultures. Two of the rabbit antipeptide sera were reproducibly reactive by western immunoblot with a diffuse (40 to 45 kDa) band of antigen found in homogenates of MARC-145 cells infected 16 h previously with the Lelystad isolate (Fig. 4) .

title:
  Antigenic differences between European and American isolates of porcine reproductive and respiratory syndrome virus (PRRSV) are encoded by the carboxyterminal portion of viral open reading frame 3

abstract:
  Antigenic differences between European and American isolates of porcine reproductive and respiratory syndrome virus (PRRSV) were revealed by serologic analysis of a recombinant protein derived from PRRSV open reading frame 3 (ORF 3). The hydrophilic carboxyterminal 199 amino acids encoded by the ORF 3 of a European (Lelystad) isolate of PRRSV were expressed as a recombinant fusion protein (BP03-P) in a baculovirus gene expression system. Sera from gnotobiotic swine exposed to prototypic reference European and American isolates of PRRSV and sera from conventionally reared European and American swine convalescing from naturally acquired PRRSV infections were used to characterize the BP03-P protein. Sera from gnotobiotic and conventionally reared swine exposed to European isolates of PRRSV were significantly more reactive (P < 0.01) with BP03-P than were the corresponding American PRRSV antisera using the indirect immunoperoxidase monolayer assay (IPMA). Prototypic European, but not American, PRRSV antisera also recognized BP03-P using western immunoblotting and radioimmunoprecipitation assay (RIPA) procedures. However, gnotobiotically derived antiserum to an atypical American-origin PRRSV was reactive with BP03-P by both IPMA and western immunoblot. Despite a predicted potential for N-linked glycosylation, studies with tunicamycin and peptide-N-glycosidase F (PNGase F) indicated that BP03-P was not N-glycosylated in either insect cell cultures or Trichoplusia ni larvae infected with the recombinant baculovirus. Sera from rabbits inoculated with BP03-P failed to neutralize both the European (Lelystad) and American (ATCC VR-2332) reference isolates of PRRSV and did not react by IPMA with PRRSV-infected cell cultures. Taken together, the data suggest that the carboxyterminal portion of PRRSV ORF 3 encodes a non-neutralizing viral peptide that is partially responsible for the serologic differences noted between European and most American isolates of PRRSV.


id: cord-009443-0vis4bwi
author: Cui, Junru
date: 2020-02-28
txt: ./txt/cord-009443-0vis4bwi.txt
cache: ./cache/cord-009443-0vis4bwi.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7157218/
doi: 10.3390/vaccines8010106
summary:
  Furthermore, vaccination with the GP5-Mosaic based vaccines resulted in protection against challenge with two heterologous virus strains, as demonstrated by the significantly lower viral loads in serum, tissues, porcine alveolar macrophages (PAMs), and bronchoalveolar lavage (BAL) fluids, and less severe lung lesions after challenge with either MN184C or VR2332, which have only 85% identity. In contrast, the viral loads in serum of animals receiving the GP5-Mosaic-vaccine were significantly lower than those of animals receiving the GP5-WT vaccine or those of vector-control animals at 7 and 14 DPC with MN184C (* p < 0.05) ( Figure 3B ), which was different compared to VR2332-challenged groups. Assessment of the efficacy of commercial porcine reproductive and respiratory syndrome virus (PRRSV) vaccines based on measurement of serologic response, frequency of gamma-IFN-producing cells and virological parameters of protection upon challenge.

title:
  Broad Protection of Pigs against Heterologous PRRSV Strains by a GP5-Mosaic DNA Vaccine Prime/GP5-Mosaic rVaccinia (VACV) Vaccine Boost

abstract:
  Background: Porcine reproductive and respiratory syndrome (PRRS) viruses are a major cause of disease and economic loss in pigs worldwide. High genetic diversity among PRRSV strains is problematic for successful disease control by vaccination. Mosaic DNA and vaccinia (VACV) vaccines were developed in order to improve protection against heterologous PRRSV strains. Methods: Piglets were primed and boosted with GP5-Mosaic DNA vaccine and recombinant GP5-Mosaic VACV (rGP5-Mosaic VACV), respectively. Pigs vaccinated with rGP5-WT (VR2332) DNA and rGP5-WT VACV, or empty vector DNA and empty VACV respectively, served as controls. Virus challenge was given to separate groups of vaccinated pigs with VR2332 or MN184C. Necropsies were performed 14 days after challenge. Results: Vaccination with the GP5-Mosaic-based vaccines resulted in cellular reactivity and higher levels of neutralizing antibodies to both VR2332 and MN184C PRRSV strains. In contrast, vaccination of animals with the GP5-WT vaccines induced responses only to VR2332. Furthermore, vaccination with the GP5-Mosaic based vaccines resulted in protection against challenge with two heterologous virus strains, as demonstrated by the significantly lower viral loads in serum, tissues, porcine alveolar macrophages (PAMs), and bronchoalveolar lavage (BAL) fluids, and less severe lung lesions after challenge with either MN184C or VR2332, which have only 85% identity. In contrast, significant protection by the GP5-WT based vaccines was only achieved against the VR2332 strain. Conclusions: GP5-Mosaic vaccines, using a DNA-prime/VACV boost regimen, conferred protection in pigs against heterologous viruses.


id: cord-010094-t0y3t9v3
title: Glycyrrhizic‐Acid‐Based Carbon Dots with High Antiviral Activity by Multisite Inhibition Mechanisms
author: Tong, Ting
date: 2020-02-20
txt: ./txt/cord-010094-t0y3t9v3.txt
cache: ./cache/cord-010094-t0y3t9v3.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7169479/
doi: 10.1002/smll.201906206
summary:
  [32, [36] [37] [38] [39] [40] [41] [43] [44] [45] [46] [47] In this study, a kind of highly biocompatible Gly-CDs was synthesized from active ingredient of Chinese herbal medicine, which combines the high biocompatibility of CDs with the excellent antiviral properties of glycyrrhizic acid and inhibit the proliferation of PRRSV by ≈5 orders of magnitude. According to the experimental design (Scheme S1, Supporting Information), the addition of Gly-CDs significantly reduced PRRSV titers in intracellular and cell supernatants at 12, 24, 36, and 48 h post infection (hpi), with a maximal reduction of ≈10 5 -fold by plaque assay (Figure 3a,b) , demonstrating the strong antiviral effect of Gly-CDs on PRRSV. Adsorption Assay: MARC-145 cells were precooled at 4 °C for 30 min, followed by infection with PRRSV (MOI = 0.001) for 2 h at 4 °C in the presence of 0.30 mg mL −1 Gly-CDs in DMEM (containing 2% FBS).

abstract:
  With the gradual usage of carbon dots (CDs) in the area of antiviral research, attempts have been stepped up to develop new antiviral CDs with high biocompatibility and antiviral effects. In this study, a kind of highly biocompatible CDs (Gly‐CDs) is synthesized from active ingredient (glycyrrhizic acid) of Chinese herbal medicine by a hydrothermal method. Using the porcine reproductive and respiratory syndrome virus (PRRSV) as a model, it is found that the Gly‐CDs inhibit PRRSV proliferation by up to 5 orders of viral titers. Detailed investigations reveal that Gly‐CDs can inhibit PRRSV invasion and replication, stimulate antiviral innate immune responses, and inhibit the accumulation of intracellular reactive oxygen species (ROS) caused by PRRSV infection. Proteomics analysis demonstrates that Gly‐CDs can stimulate cells to regulate the expression of some host restriction factors, including DDX53 and NOS3, which are directly related to PRRSV proliferation. Moreover, it is found that Gly‐CDs also remarkably suppress the propagation of other viruses, such as pseudorabies virus (PRV) and porcine epidemic diarrhea virus (PEDV), suggesting the broad antiviral activity of Gly‐CDs. The integrated results demonstrate that Gly‐CDs possess extraordinary antiviral activity with multisite inhibition mechanisms, providing a promising candidate for alternative therapy for PRRSV infection.


id: cord-012909-o6t2srim
author: Chaudhari, Jayeshbhai
date: 2020-07-28
txt: ./txt/cord-012909-o6t2srim.txt
cache: ./cache/cord-012909-o6t2srim.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7474429/
doi: 10.3390/v12080817
summary:
  Both virulent and live-attenuated porcine reproductive and respiratory syndrome virus (PRRSV) strains can establish persistent infection in lymphoid tissues of pigs. In this study, expression of several important chemokine ligands (CCL19, CCL21, CCL24, CCL22, CX3CL1, and CCL14) and chemokine receptors (CCR6 and CCR10) which play an essential role in migration and localization of lymphocytes and antigen-presenting cells (APCs) to the lymphoid tissues was down regulated in ILN of CON90-infected pigs (Figure 6a ). In this study, expression of several important chemokine ligands (CCL19, CCL21, CCL24, CCL22, CX3CL1, and CCL14) and chemokine receptors (CCR6 and CCR10) which play an essential role in migration and localization of lymphocytes and antigen-presenting cells (APCs) to the lymphoid tissues was down regulated in ILN of CON90-infected pigs (Figure 6a ). GO terms and KEGG analysis revealed that genes involved in the innate immune (complement and TLR) pathways, apoptosis, cytokine-chemokine signaling, T-cell exhaustion, and humoral responses are highly differentially expressed in PRRSV-infected animals compared to control.

title:
  Host Transcriptional Response to Persistent Infection with a Live-Attenuated Porcine Reproductive and Respiratory Syndrome Virus Strain

abstract:
  Both virulent and live-attenuated porcine reproductive and respiratory syndrome virus (PRRSV) strains can establish persistent infection in lymphoid tissues of pigs. To investigate the mechanisms of PRRSV persistence, we performed a transcriptional analysis of inguinal lymphoid tissue collected from pigs experimentally infected with an attenuated PRRSV strain at 46 days post infection. A total of 6404 differentially expressed genes (DEGs) were detected of which 3960 DEGs were upregulated and 2444 DEGs were downregulated. Specifically, genes involved in innate immune responses and chemokines and receptors associated with T-cell homing to lymphoid tissues were down regulated. As a result, homing of virus-specific T-cells to lymphoid tissues seems to be ineffective, evidenced by the lower frequencies of virus-specific T-cell in lymphoid tissue than in peripheral blood. Genes associated with T-cell exhaustion were upregulated. Likewise, genes involved in the anti-apoptotic pathway were upregulated. Collectively, the data suggested that the live-attenuated PRRSV strain establishes a pro-survival microenvironment in lymphoid tissue by suppressing innate immune responses, T-cell homing, and preventing cell apoptosis.


id: cord-029839-jxqi9exm
author: Wang, Ye
date: 2019-09-26
txt: ./txt/cord-029839-jxqi9exm.txt
cache: ./cache/cord-029839-jxqi9exm.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7386707/
doi: 10.1016/j.vas.2019.100074
summary:
  Conversely, the mRNA level of PRRSV in shRNA treated Tp-PBMCs dramatically decreased, and there were significant increases of the transcription of immune genes, such as interleukin-2 (IL-2), interleukin-4 (IL-4), interferon-alpha (IFN-α), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), toll-like receptor 3 (TLR3), toll-like receptor 7 (TLR7), Myeloid differentiation primary response gene (88) (MyD88), and interleukin-27p28 (IL-27p28). Therefore the knockdown of TGF-β1 gene expression by shRNA not only inhibits the replication of PRRSV but also improves immune responsiveness following viral infection, suggesting a novel way to facilitate the control of PRRSV infection in pigs. As Table 3 The relative mRNA levels of immune genes in Tp-PBMCs transfected with shTFGβ1-1 and pNeg plasmid and cultured for 48 h. Our experiment firstly screened out effective specific shRNA targeted to pig TGF-β1 gene, it could significantly knock down the mRNA level of TGF-β1 gene and obviously increase the viability of PRRSV infected cells.

title:
  Silence of TGF-β1 gene expression reduces prrsv replication and potentiates immunity of immune cells of tibetan pig

abstract:
  Transforming growth factor beta 1 (TGF-β1) was of importance in the pathogenesis of porcine reproductive and respiratory syndrome virus (PRRSV). To determine whether knockdown of TGF-β1 gene expression could facilitate the control of PRRSV infection, specific sequences for expressing shRNA targeted to porcine TGF-β1 gene were synthesized and cloned into pSilencer 3.1-H1 neovector. Then they were used to transfect peripheral blood mononuclear cells of Tibetan pig (Tp-PBMCs) followed by PRRSV inoculation. The positive recombinant plasmids were screened for inhibition of TGF-β1 gene expression by real-time quantitative RT-PCR. Conversely, the mRNA level of PRRSV in shRNA treated Tp-PBMCs dramatically decreased, and there were significant increases of the transcription of immune genes, such as interleukin-2 (IL-2), interleukin-4 (IL-4), interferon-alpha (IFN-α), interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), toll-like receptor 3 (TLR3), toll-like receptor 7 (TLR7), Myeloid differentiation primary response gene (88) (MyD88), and interleukin-27p28 (IL-27p28). However, the expressions of IL-8 and IL-10 genes significantly reduced in comparison to the control infected cells. In addition, transfection with the shRNA plasmids significantly elevated the viability of immune cells. Therefore the knockdown of TGF-β1 gene expression by shRNA not only inhibits the replication of PRRSV but also improves immune responsiveness following viral infection, suggesting a novel way to facilitate the control of PRRSV infection in pigs.


id: cord-033692-txfuuu7d
author: Lim, Byeonghwi
date: 2020-10-13
url: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7552595/
doi: 10.1186/s13567-020-00850-5
title:
  Integrated time-serial transcriptome networks reveal common innate and tissue-specific adaptive immune responses to PRRSV infection

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) infection is the most important viral disease causing severe economic losses in the swine industry. However, mechanisms underlying gene expression control in immunity-responsible tissues at different time points during PRRSV infection are poorly understood. We constructed an integrated gene co-expression network and identified tissue- and time-dependent biological mechanisms of PRRSV infection through bioinformatics analysis using three tissues (lungs, bronchial lymph nodes [BLNs], and tonsils) via RNA-Seq. Three groups with specific expression patterns (i.e., the 3-dpi, lung, and BLN groups) were discovered. The 3 dpi-specific group showed antiviral and innate-immune signalling similar to the case for influenza A infection. Moreover, we observed adaptive immune responses in the lung-specific group based on various cytokines, while the BLN-specific group showed down-regulated AMPK signalling related to viral replication. Our study may provide comprehensive insights into PRRSV infection, as well as useful information for vaccine development.


id: cord-252339-l3si3jpn
author: Xu, Ao-Tian
date: 2010-09-24
url: https://www.ncbi.nlm.nih.gov/pubmed/20865444/
doi: 10.1007/s10529-010-0370-1
title:
  Characterization of the biochemical properties and identification of amino acids forming the catalytic center of 3C-like proteinase of porcine reproductive and respiratory syndrome virus

abstract:
  The non-structural protein 4 (Nsp4) of porcine reproductive and respiratory syndrome virus (PRRSV) functions as a 3C-like proteinase (3CLpro) and plays a pivotal role in gene expression and replication. We have examined the biochemical properties of PRRSV 3CLpro and identified those amino acid residues involved in its catalytic activity as a prelude to developing anti-PRRSV strategies. The 3C-like proteinase (3CLpro) of porcine reproductive and respiratory syndrome virus (PRRSV) was expressed in Escherichia coli and characterized. The optimal temperature and pH for its proteolytic activity were 8°C and 7.5, respectively. Na(+) (1000 mM) and K(+) (500 mM) were not inhibitory to its activity but Cu(2+), Zn(2+), PMSF and EDTA were significantly inhibitory. His(39), Asp(64) and Ser(118) residues were identified to form the catalytic triad of PRRSV 3CLpro by a series of site-directed mutagenesis analysis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10529-010-0370-1) contains supplementary material, which is available to authorized users.


id: cord-255793-fi1vo0gx
author: Shi, Xibao
date: 2015-04-30
url: https://api.elsevier.com/content/article/pii/S0034528815000405
doi: 10.1016/j.rvsc.2015.01.015
title:
  Small interfering RNA targeting nonstructural protein1 α (nsp1α) of porcine reproductive and respiratory syndrome virus (PRRSV) can reduce the replication of PRRSV in MARC-145 cells

abstract:
  Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most economically devastating and pandemic diseases of swine, which is poorly controlled by current methods. The inhibition of specific genes by small interfering RNA (siRNA) has been proven to be a potential therapeutic strategy against viral infection. Previous studies have indicated that the nonstructural protein 1α (nsp1α) of PRRSV may take an important role in virulence of PRRSV. The present work was involved to explore the effect of siRNA targeting nsp1α on the replication of PRRSV in MARC-145 cells, and the results showed that over-expression of nsp1α enhanced the replication of PRRSV and that siRNAs specifically targeting nsp1α significantly inhibited the replication of PRRSV in MARC-145 cells. In conclusion, this work indicated that nsp1α may be a viral pathogenicity factor of PRRSV and that siRNAs specifically targeting nsp1α may be a new strategy to control PRRSV in the future.


id: cord-255828-jrqdyfbg
author: Du, Yijun
date: 2012-03-01
url: https://api.elsevier.com/content/article/pii/S0042682211005691
doi: 10.1016/j.virol.2011.12.009
title:
  Glycosyl-phosphatidylinositol (GPI)-anchored membrane association of the porcine reproductive and respiratory syndrome virus GP4 glycoprotein and its co-localization with CD163 in lipid rafts

abstract:
  The porcine reproductive and respiratory syndrome virus (PRRSV) glycoprotein 4 (GP4) resembles a typical type I membrane protein in its structure but lacks a hydrophilic tail at the C-terminus, suggesting that GP4 may be a lipid-anchored membrane protein. Using the human decay-accelerating factor (DAF; CD55), a known glycosyl-phosphatidylinositol (GPI) lipid-anchored protein, chimeric constructs were made to substitute the GPI-anchor domain of DAF with the putative lipid-anchor domain of GP4, and their membrane association and lipase cleavage were determined in cells. The DAF-GP4 fusion protein was transported to the plasma membrane and was cleaved by phosphatidylinositol-specific phospholipase C (PI-PLC), indicating that the C-terminal domain of GP4 functions as a GPI anchor. Mutational studies for residues adjacent to the GPI modification site and characterization of respective mutant viruses generated from infectious cDNA clones show that the ability of GP4 for membrane association corresponded to virus viability and growth characteristics. The residues T158 (ω − 2, where ω is the GPI moiety at E160), P159 (ω − 1), and M162 (ω + 2) of GP4 were determined to be important for virus replication, with M162 being of particular importance for virus infectivity. The complete removal of the peptide–anchor domain in GP4 resulted in a complete loss of virus infectivity. The depletion of cholesterol from the plasma membrane of cells reduced the virus production, suggesting a role of lipid rafts in PRRSV infection. Remarkably, GP4 was found to co-localize with CD163 in the lipid rafts on the plasma membrane. Since CD163 has been reported as a cellular receptor for PRRSV and GP4 has been shown to interact with this receptor, our data implicates an important role of lipid rafts during entry of the virus.


id: cord-255857-y9wjp0aj
author: Yuan, Shishan
date: 2001-11-05
txt: ./txt/cord-255857-y9wjp0aj.txt
cache: ./cache/cord-255857-y9wjp0aj.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/11551659/
doi: 10.1016/s0168-1702(01)00295-7
summary:
  Two full-length porcine reproductive and respiratory syndrome virus (PRRSV) genomes, strain VR-2332 and its cell culture passaged descendent RespPRRS vaccine strain, were compared and analyzed in order to identify possible sites of attenuation. However, the cluster of amino acid mutations located near the carboxyl terminal end suggests that the replicase region was altered during passage to result in a more fit virus for replication in cell culture, as evidenced by the in vitro one-step growth curve comparison shown in Fig. 4 . Sequence analysis of strains VR-2332 and RespPRRS indicated that there were 15 nucleotide changes in this region, and all but one of which resulted in amino acid alterations. Attenuation can result from changes in many areas of viral genomes and the 41 nucleotide mutations described include alterations in several key PRRSV regions.

title:
  Erratum to “Complete genome comparison of porcine reproductive and respiratory syndrome virus parental and attenuated strains”

abstract:
  Two full-length porcine reproductive and respiratory syndrome virus (PRRSV) genomes, strain VR-2332 and its cell culture passaged descendent RespPRRS vaccine strain, were compared and analyzed in order to identify possible sites of attenuation. Of the 41 nucleotide changes, 12 resulted in conservative changes and 18 produced non-conservative changes. The results suggest that key amino acids in ORF1 may contribute to the phenotype of RespPRRS, which includes increased growth rate on MA-104 cells and decreased virulence in swine. The results provide a genetic basis for future manipulation of a PRRSV reverse genetics system.


id: cord-257220-fe2sacjj
title: Porcine reproductive and respiratory syndrome (PRRS): an immune dysregulatory pandemic
author: Butler, J. E.
date: 2014-07-01
txt: ./txt/cord-257220-fe2sacjj.txt
cache: ./cache/cord-257220-fe2sacjj.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/24981123/
doi: 10.1007/s12026-014-8549-5
summary:
  LDV elevates IgG levels in mice with little production of virus-specific antibodies [11, 21] , which is almost identical to what is seen in isolator piglets infected with PRRSV [22] (''''The effect of age, rearing, complement and the role of mucosal immunity'''' section). Polyclonal activation of B cells occurs in lymphoid organs from porcine reproductive and respiratory syndrome virus (PRRSV)-induced pigs The presence of alpha interferon at the time of infection alters the innate and adaptive immune responses to porcine reproductive and respiratory syndrome virus Interferon type I response in porcine reproductive and respiratory syndrome virus-infected MARC-145 cells Antigen-specific B cell responses to porcine reproductive and respiratory syndrome virus infection Antibody production and blastogenesis response in pigs experimentally infected with porcine reproductive and respiratory syndrome virus Neutralizing antibody responses of pigs infected with natural GP5 N-glycan mutants of porcine reproductive and respiratory syndrome virus

abstract:
  Porcine reproductive and respiratory disease syndrome (PRRS) is a viral pandemic that especially affects neonates within the “critical window” of immunological development. PRRS was recognized in 1987 and within a few years became pandemic causing an estimated yearly $600,000 economic loss in the USA with comparative losses in most other countries. The causative agent is a single-stranded, positive-sense enveloped arterivirus (PRRSV) that infects macrophages and plasmacytoid dendritic cells. Despite the discovery of PRRSV in 1991 and the publication of >2,000 articles, the control of PRRS is problematic. Despite the large volume of literature on this disease, the cellular and molecular mechanisms describing how PRRSV dysregulates the host immune system are poorly understood. We know that PRRSV suppresses innate immunity and causes abnormal B cell proliferation and repertoire development, often lymphopenia and thymic atrophy. The PRRSV genome is highly diverse, rapidly evolving but amenable to the generation of many mutants and chimeric viruses for experimental studies. PRRSV only replicates in swine which adds to the experimental difficulty since no inbred well-defined animal models are available. In this article, we summarize current knowledge and apply it toward developing a series of provocative and testable hypotheses to explain how PRRSV immunomodulates the porcine immune system with the goal of adding new perspectives on this disease.


id: cord-257886-ytlnhyxr
author: Zhao, Kuan
date: 2019-05-03
txt: ./txt/cord-257886-ytlnhyxr.txt
cache: ./cache/cord-257886-ytlnhyxr.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1016/j.vetmic.2019.05.003
doi: 10.1016/j.vetmic.2019.05.003
summary:
  title: Nucleocapsid protein of porcine reproductive and respiratory syndrome virus antagonizes the antiviral activity of TRIM25 by interfering with TRIM25-mediated RIG-I ubiquitination These results indicate for the first time that TRIM25 inhibits PRRSV replication and that the N protein antagonizes the antiviral activity by interfering with TRIM25-mediated RIG-I ubiquitination. The cells were lysed in RIPA lysis buffer after 36 h of transfection and the effects of siRNAs were analyzed by WB using an anti-TRIM25 monoclonal antibody (cat. To investigate whether TRIM25-mediated RIG-I ubiquitination is regulated by the PRRSV N protein, HEK293T cells grown in 6-well plates were co-transfected with pCAGGS-Flag-RIG-I (0.5 μg per well) and HA-ubiquitin (0.5 μg per well), and the indicated amounts of the Myc-N expression plasmids. The experiment revealed that TRIM25-mediated RIG-I ubiquitination was potentiated by Sendai virus (SEV) infection but was substantially suppressed by increasing the PRRSV N protein expression, in a dose-dependent manner (Fig. 5) .

title:
  Nucleocapsid protein of porcine reproductive and respiratory syndrome virus antagonizes the antiviral activity of TRIM25 by interfering with TRIM25-mediated RIG-I ubiquitination

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) is caused by PRRS virus (PRRSV), and is characterized by respiratory diseases in piglet and reproductive disorders in sow. Identification of sustainable and effective measures to mitigate PRRSV transmission is a pressing problem. The nucleocapsid (N) protein of PRRSV plays a crucial role in inhibiting host innate immunity during PRRSV infection. In the current study, a new host-restricted factor, tripartite motif protein 25 (TRIM25), was identified as an inhibitor of PRRSV replication. Co-immunoprecipitation assay indicated that the PRRSV N protein interferes with TRIM25–RIG-I interactions by competitively interacting with TRIM25. Furthermore, N protein inhibits the expression of TRIM25 and TRIM25-mediated RIG-I ubiquitination to suppress interferon β production. Furthermore, with increasing TRIM25 expression, the inhibitory effect of N protein on the ubiquitination of RIG-I diminished. These results indicate for the first time that TRIM25 inhibits PRRSV replication and that the N protein antagonizes the antiviral activity by interfering with TRIM25-mediated RIG-I ubiquitination. This not only provides a theoretical basis for the development of drugs to control PRRSV replication, but also better explains the mechanism through which the PRRSV N protein inhibits innate immune responses of the host.


id: cord-258536-qnn9hp8e
title: The Interaction between Nidovirales and Autophagy Components
author: Cong, Yingying
date: 2017-07-11
url: https://www.ncbi.nlm.nih.gov/pubmed/28696396/
doi: 10.3390/v9070182
abstract:
  Autophagy is a conserved intracellular catabolic pathway that allows cells to maintain homeostasis through the degradation of deleterious components via specialized double-membrane vesicles called autophagosomes. During the past decades, it has been revealed that numerous pathogens, including viruses, usurp autophagy in order to promote their propagation. Nidovirales are an order of enveloped viruses with large single-stranded positive RNA genomes. Four virus families (Arterividae, Coronaviridae, Mesoniviridae, and Roniviridae) are part of this order, which comprises several human and animal pathogens of medical and veterinary importance. In host cells, Nidovirales induce membrane rearrangements including autophagosome formation. The relevance and putative mechanism of autophagy usurpation, however, remain largely elusive. Here, we review the current knowledge about the possible interplay between Nidovirales and autophagy.


id: cord-259296-qsaewje2
title: Tomatidine inhibits porcine epidemic diarrhea virus replication by targeting 3CL protease
author: Wang, Pengcheng
date: 2020-11-11
url: https://doi.org/10.1186/s13567-020-00865-y
doi: 10.1186/s13567-020-00865-y
abstract:
  Porcine epidemic diarrhea virus (PEDV) causes lethal diarrhea in suckling piglets, leading to severe economic losses worldwide. There is an urgent need to find new therapeutic methods to prevent and control PEDV. Not only is there a shortage of commercial anti-PEDV drugs, but available commercial vaccines fail to protect against highly virulent PEDV variants. We screened an FDA-approved library of 911 natural products and found that tomatidine, a steroidal alkaloid extracted from the skin and leaves of tomatoes, demonstrates significant inhibition of PEDV replication in Vero and IPEC-J2 cells in vitro. Molecular docking and molecular dynamics analysis predicted interactions between tomatidine and the active pocket of PEDV 3CL protease, which were confirmed by fluorescence spectroscopy and isothermal titration calorimetry (ITC). The inhibiting effect of tomatidine on 3CL protease was determined using cleavage visualization and FRET assay. Tomatidine-mediated blocking of 3CL protease activity in PEDV-infected cells was examined by western blot detection of the viral polyprotein in PEDV-infected cells. It indicates that tomatidine inhibits PEDV replication mainly by targeting 3CL protease. In addition, tomatidine also has antiviral activity against transmissible gastroenteritis virus (TGEV), porcine reproductive and respiratory syndrome virus (PRRSV), encephalo myocarditis virus (EMCV) and seneca virus A (SVA) in vitro. These results may be helpful in developing a new prophylactic and therapeutic strategy against PEDV and other swine disease infections.


id: cord-259771-653opx0h
author: Dwivedi, Varun
date: 2012-12-11
txt: ./txt/cord-259771-653opx0h.txt
cache: ./cache/cord-259771-653opx0h.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/23240064/
doi: 10.1371/journal.pone.0051794
summary:
  In a pre-challenge study, intranasal delivery of Nano-KAg resulted in induction of innate immune response at both mucosal and systemic sites, indicated by a significant increase in the frequency of NK cells, DCs, and cd T cells in the lung MNC ( Figure 2 , A-C); and cd T cells and DCs in the PBMC compared to K-Ag vaccinated pigs (Figure 2, H & I) . Lung homogenates of Nano-KAg immunized pigs contained significantly higher levels of virus specific IgA and IgG antibodies compared to unvaccinated and K-Ag vaccinated, MN184 challenged pigs (Figure 4, A & B) . The frequency of cd T cells and CD4 + (but not CD8 + ) T cells in the lungs of Nano-KAg vaccinated animals were significantly increased compared to K-Ag and unvaccinated, virus challenged pigs ( Figure 5 , D, E & F).

title:
  Biodegradable Nanoparticle-Entrapped Vaccine Induces Cross-Protective Immune Response against a Virulent Heterologous Respiratory Viral Infection in Pigs

abstract:
  Biodegradable nanoparticle-based vaccine development research is unexplored in large animals and humans. In this study, we illustrated the efficacy of nanoparticle-entrapped UV-killed virus vaccine against an economically important respiratory viral disease of pigs called porcine reproductive and respiratory syndrome virus (PRRSV). We entrapped PLGA [poly (lactide-co-glycolides)] nanoparticles with killed PRRSV antigens (Nano-KAg) and detected its phagocytosis by pig alveolar macrophages. Single doses of Nano-KAg vaccine administered intranasally to pigs upregulated innate and PRRSV specific adaptive responses. In a virulent heterologous PRRSV challenge study, Nano-KAg vaccine significantly reduced the lung pathology and viremia, and the viral load in the lungs. Immunologically, enhanced innate and adaptive immune cell population and associated cytokines with decreased secretion of immunosuppressive mediators were observed at both mucosal sites and blood. In summary, we demonstrated the benefits of intranasal delivery of nanoparticle-based viral vaccine in eliciting cross-protective immune response in pigs, a potential large animal model.


id: cord-260840-tudl9k1g
author: Opriessnig, Tanja
date: 2012-07-06
txt: ./txt/cord-260840-tudl9k1g.txt
cache: ./cache/cord-260840-tudl9k1g.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/22406346/
doi: 10.1016/j.vetmic.2012.02.010
summary:
  More recently, attention has focused on the occurrence of high mortality in Chinese swine herds which Veterinary Microbiology 158 (2012) [69] [70] [71] [72] [73] [74] [75] [76] [77] [78] [79] [80] [81] To determine differences in infection kinetics of two temporally and genetically different type 2 porcine reproductive and respiratory syndrome virus (PRRSV) isolates in vivo with and without concurrent porcine circovirus (PCV) type 2a or 2b infection, 62 pigs were randomly assigned to one of seven groups: negative controls (n = 8); pigs coinfected with a 1992 PRRSV strain (VR-2385) and PCV2a (CoI-92-2a; n = 9), pigs coinfected with VR-2385 and PCV2b (CoI-92-2b; n = 9), pigs coinfected with a 2006 PRRSV strain (NC16845b) and PCV2a (CoI-06-2a; n = 9), pigs coinfected with NC16845b and PCV2b (CoI-06-2b; n = 9), pigs infected with VR-2385 (n = 9), and pigs infected with NC16845b (n = 9).

title:
  Effect of porcine circovirus type 2a or 2b on infection kinetics and pathogenicity of two genetically divergent strains of porcine reproductive and respiratory syndrome virus in the conventional pig model

abstract:
  To determine differences in infection kinetics of two temporally and genetically different type 2 porcine reproductive and respiratory syndrome virus (PRRSV) isolates in vivo with and without concurrent porcine circovirus (PCV) type 2a or 2b infection, 62 pigs were randomly assigned to one of seven groups: negative controls (n = 8); pigs coinfected with a 1992 PRRSV strain (VR-2385) and PCV2a (CoI-92-2a; n = 9), pigs coinfected with VR-2385 and PCV2b (CoI-92-2b; n = 9), pigs coinfected with a 2006 PRRSV strain (NC16845b) and PCV2a (CoI-06-2a; n = 9), pigs coinfected with NC16845b and PCV2b (CoI-06-2b; n = 9), pigs infected with VR-2385 (n = 9), and pigs infected with NC16845b (n = 9). Blood samples were collected before inoculation and at day post-inoculation (dpi) 3, 6, 9 and 12 and tested for the presence of PRRSV antibody and RNA, PCV2 antibody and DNA, complete blood counts, and interferon gamma (IFN-γ) levels. Regardless of concurrent PCV2 infection, VR-2385 initially replicated at higher levels and reached peak replication levels at dpi 6. Pigs infected with VR-2385 had significantly higher amounts of viral RNA in serum on both dpi 3 and dpi 6, compared to pigs infected with NC16845b. The peak of NC16845b virus replication occurred between dpi 9 and dpi 12 and was associated with a delayed anti-PRRSV antibody response in these pigs. PCV2 coinfection resulted in significantly more severe macroscopic and microscopic lung lesions and a stronger anti-PRRSV IgG response compared to pigs infected with PRRSV alone. This work further emphasizes in vivo replication differences among PRRSV strains and the importance of coinfecting pathogens.


id: cord-261160-g92zhv19
author: Rowland, Raymond R.R
date: 2003-10-30
txt: ./txt/cord-261160-g92zhv19.txt
cache: ./cache/cord-261160-g92zhv19.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/14559170/
doi: 10.1016/j.vetmic.2003.07.006
summary:
  title: Lymphoid tissue tropism of porcine reproductive and respiratory syndrome virus replication during persistent infection of pigs originally exposed to virus in utero Even though PRRSV-specific antibody appears as early as 5 days post-infection and is followed by serum neutralizing activity and cell-mediated immunity Molitor, 1997, 1999; Rowland et al., 1999 Rowland et al., , 2001 persistently infected pigs can continue to shed virus. The purpose of this study was to further understand persistent infection in congenitally infected pigs by characterizing the course of clinical disease, sites of virus replication and the capacity to transmit virus in a group of pigs exposed to PRRSV in utero. Analysis of virus and antibody in blood and/or umbilical cords from the 28 live neonates showed that at least 20 or 74% were virus isolation (VI) or RT-PCR positive for PRRSV at the time of farrowing indicating that in utero infection was successful.

title:
  Lymphoid tissue tropism of porcine reproductive and respiratory syndrome virus replication during persistent infection of pigs originally exposed to virus in utero

abstract:
  The ability of porcine reproductive and respiratory syndrome virus (PRRSV) to establish a persistent infection is the principal contributing factor to the world-wide spread of the disease. Several studies have documented the course of viral infection in postnatally infected pigs; however, very little is known regarding sites of virus replication during persistent infection of pigs exposed to PRRSV in utero. In this study, virus replication and PRRSV-specific antibody were followed for several hundred days in a group of pigs derived from three sows infected at 90 days of gestation with PRRSV isolate VR-2332. Eighty-four percent of pigs were born viremic with a mortality of 54% within 21 days after birth. At approximately 60 days sera from pigs were negative for virus by virus isolation. Analysis of virus replication in the tissues of pigs randomly sacrificed between 63 and 132 days showed no evidence of virus in lung and other non-lymphoid organs. However, virus was easily recovered from tonsil and lymph nodes and in situ hybridization identified these tissues as sites of virus replication. Even though replication was at a low level, virus was easily transmitted to sentinel pigs. By 260 days pigs became seronegative and did not transmit virus to sentinel pigs. Sacrifice of remaining pigs after 300 days showed no evidence of virus in blood and tissues. This study shows that congenital PRRSV-infected pigs can support virus replication for an extended period during which virus replication is primarily restricted to tonsil and lymph nodes.


id: cord-262021-emboxdzu
author: Gómez-Laguna, Jaime
date: 2012-12-20
url: https://api.elsevier.com/content/article/pii/S1090023312004844
doi: 10.1016/j.tvjl.2012.11.012
title:
  Immunopathogenesis of porcine reproductive and respiratory syndrome in the respiratory tract of pigs

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) impairs local pulmonary immune responses by damaging the mucociliary transport system, impairing the function of porcine alveolar macrophages and inducing apoptosis of immune cells. An imbalance between pro- and anti-inflammatory cytokines, including tumour necrosis factor-α and interleukin-10, in PRRS may impair the immune response of the lung. Pulmonary macrophage subpopulations have a range of susceptibilities to different PRRSV strains and different capacities to express cytokines. Infection with PRRSV decreases the bactericidal activity of macrophages, which increases susceptibility to secondary bacterial infections. PRRSV infection is associated with an increase in concentrations of haptoglobin, which may interact with the virus receptor (CD163) and induce the synthesis of anti-inflammatory mediators. The balance between pro- and anti-inflammatory cytokines modulates the expression of CD163, which may affect the pathogenicity and replication of the virus in different tissues. With the emergence of highly pathogenic PRRSV, there is a need for more information on the immunopathogenesis of different strains of PRRS, particularly to develop more effective vaccines.


id: cord-262347-ejhz9rra
title: PRRSV structure, replication and recombination: Origin of phenotype and genotype diversity
author: Kappes, Matthew A.
date: 2015-03-07
txt: ./txt/cord-262347-ejhz9rra.txt
cache: ./cache/cord-262347-ejhz9rra.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1016/j.virol.2015.02.012
doi: 10.1016/j.virol.2015.02.012
summary:
  The nidovirus order constitutes a group of singlestranded positive-sense RNA viruses which share a hallmark replication/transcription strategy, similar genomic organization, and a defining set of genetic elements, but differ in host species and range, disease phenotype, virion morphology, cellular tropism, genomic size and encoded content . It has been shown that the EAV replicase proteins (ORF1a/b) are sufficient to support viral replication (Molenkamp et al., 2000b) , but that infectivity is dependent on the presence of the structural genes encoded at the 3 0 -end of the arterivirus genome Molenkamp et al., 2000b; Verheije et al., 2002) . Leader-body junction sequence of the viral subgenomic mRNAs of porcine reproductive and respiratory syndrome virus isolated in Taiwan Molecular cloning and nucleotide sequencing of the 3 0 -terminal genomic RNA of the porcine reproductive and respiratory syndrome virus Comparison of the 5 0 leader sequences of North American isolates of reference and field strains of porcine reproductive and respiratory syndrome virus (PRRSV)

abstract:
  Porcine reproductive and respiratory disease virus (PRRSV) has the intrinsic ability to adapt and evolve. After 25 years of study, this persistent pathogen has continued to frustrate efforts to eliminate infection of herds through vaccination or other elimination strategies. The purpose of this review is to summarize the research on the virion structure, replication and recombination properties of PRRSV that have led to the extraordinary phenotype and genotype diversity that exists worldwide.


id: cord-264598-2u8bm2fz
author: Sánchez-Carvajal, J.M.
date: 2020-06-02
url: https://doi.org/10.1016/j.vetmic.2020.108744
doi: 10.1016/j.vetmic.2020.108744
title:
  Activation of pro- and anti-inflammatory responses in lung tissue injury during the acute phase of PRRSV-1 infection with the virulent strain Lena

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) plays a key role in porcine respiratory disease complex modulating the host immune response and favouring secondary bacterial infections. Pulmonary alveolar macrophages (PAMs) are the main cells supporting PRRSV replication, with CD163 as the essential receptor for viral infection. Although interstitial pneumonia is by far the representative lung lesion, suppurative bronchopneumonia is described for PRRSV virulent strains. This research explores the role of several immune markers potentially involved in the regulation of the inflammatory response and sensitisation of lung to secondary bacterial infections by PRRSV-1 strains of different virulence. Conventional pigs were intranasally inoculated with the virulent subtype 3 Lena strain or the low virulent subtype 1 3249 strain and euthanised at 1, 3, 6 and 8 dpi. Lena-infected pigs exhibited more severe clinical signs, macroscopic lung score and viraemia associated with an increase of IL-6 and IFN-γ in sera compared to 3249-infected pigs. Extensive areas of lung consolidation corresponding with suppurative bronchopneumonia were observed in Lena-infected pigs. Lung viral load and PRRSV-N-protein(+) cells were always higher in Lena-infected animals. PRRSV-N-protein(+) cells were linked to a marked drop of CD163(+) macrophages. The number of CD14(+) and iNOS(+) cells gradually increased along PRRSV-1 infection, being more evident in Lena-infected pigs. The frequency of CD200R1(+) and FoxP3(+) cells peaked late in both PRRSV-1 strains, with a strong correlation between CD200R1(+) cells and lung injury in Lena-infected pigs. These results highlight the role of molecules involved in the earlier and higher extent of lung lesions in piglets infected with the virulent Lena strain, pointing out the activation of routes potentially involved in the restraint of the local inflammatory response.


id: cord-266199-smlq11y9
title: Nanoparticle-based vaccine development and evaluation against viral infections in pigs
author: Dhakal, Santosh
date: 2019-11-06
url: https://www.ncbi.nlm.nih.gov/pubmed/31694705/
doi: 10.1186/s13567-019-0712-5
abstract:
  Virus infections possess persistent health challenges in swine industry leading to severe economic losses worldwide. The economic burden caused by virus infections such as Porcine Reproductive and Respiratory Syndrome Virus, Swine influenza virus, Porcine Epidemic Diarrhea Virus, Porcine Circovirus 2, Foot and Mouth Disease Virus and many others are associated with severe morbidity, mortality, loss of production, trade restrictions and investments in control and prevention practices. Pigs can also have a role in zoonotic transmission of some viral infections to humans. Inactivated and modified-live virus vaccines are available against porcine viral infections with variable efficacy under field conditions. Thus, improvements over existing vaccines are necessary to: (1) Increase the breadth of protection against evolving viral strains and subtypes; (2) Control of emerging and re-emerging viruses; (3) Eradicate viruses localized in different geographic areas; and (4) Differentiate infected from vaccinated animals to improve disease control programs. Nanoparticles (NPs) generated from virus-like particles, biodegradable and biocompatible polymers and liposomes offer many advantages as vaccine delivery platform due to their unique physicochemical properties. NPs help in efficient antigen internalization and processing by antigen presenting cells and activate them to elicit innate and adaptive immunity. Some of the NPs-based vaccines could be delivered through both parenteral and mucosal routes to trigger efficient mucosal and systemic immune responses and could be used to target specific immune cells such as mucosal microfold (M) cells and dendritic cells (DCs). In conclusion, NPs-based vaccines can serve as novel candidate vaccines against several porcine viral infections with the potential to enhance the broader protective efficacy under field conditions. This review highlights the recent developments in NPs-based vaccines against porcine viral pathogens and how the NPs-based vaccine delivery system induces innate and adaptive immune responses resulting in varied level of protective efficacy.


id: cord-266716-pghnl980
author: Wang, Hai-Ming
date: 2018-02-06
txt: ./txt/cord-266716-pghnl980.txt
cache: ./cache/cord-266716-pghnl980.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/29411137/
doi: 10.1007/s00705-018-3755-4
summary:
  title: Isobavachalcone inhibits post-entry stages of the porcine reproductive and respiratory syndrome virus life cycle Since the first report of a porcine reproductive and respiratory syndrome (PRRS) outbreak, tremendous efforts to control this disease, including various national policies and plans incorporating the use of multiple modified live-virus vaccines, have been made. Western blot analysis revealed that PRRSV N protein levels decreased markedly, indicating that increasing concentrations of IBC significantly inhibited PRRSV replication (Fig. 1F) . The in vitro study established that IBC efficiently inhibited the replication of both HP-PRRSV and the current Chinese epidemic NADC30-like strains without significant drug toxicity. Role of phosphatidylinositol 3-kinase (PI3K) and Akt1 kinase in porcine reproductive and respiratory syndrome virus (PRRSV) replication Pathogenicity and antigenicity of a novel NADC30-like strain of porcine reproductive and respiratory syndrome virus emerged in China NADC30-like strain of porcine reproductive and respiratory syndrome virus

title:
  Isobavachalcone inhibits post-entry stages of the porcine reproductive and respiratory syndrome virus life cycle

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) is a pathogen of great economic significance that impacts the swine industry globally. Since the first report of a porcine reproductive and respiratory syndrome (PRRS) outbreak, tremendous efforts to control this disease, including various national policies and plans incorporating the use of multiple modified live-virus vaccines, have been made. However, PRRSV is still a significant threat to the swine industry, and new variants continually emerge as a result of PRRSV evolution. Several studies have shown that pandemic PRRSV strains have enormous genetic diversity and that commercial vaccines can only provide partial protection against these strains. Therefore, effective anti-PRRSV drugs may be more suitable and reliable for PRRSV control. In this study, we observed that isobavachalcone (IBC), which was first isolated from Psoralea corylifolia, had potent anti-PRRSV activity in vitro. Although many biological activities of IBC have been reported, this is the first report describing the antiviral activity of IBC. Furthermore, after a systematic investigation, we demonstrated that IBC inhibits PRRSV replication at the post-entry stage of PRRSV infection. Thus, IBC may be a candidate for further evaluation as a therapeutic agent against PRRSV infection of swine in vivo.


id: cord-269560-vq462fh2
title: Pathogenicity of three genetically diverse strains of PRRSV Type 1 in specific pathogen free pigs
author: Stadejek, Tomasz
date: 2017-05-16
url: https://www.sciencedirect.com/science/article/pii/S0378113517305357
doi: 10.1016/j.vetmic.2017.05.011
abstract:
  Studies from Eastern European countries proved that porcine reproductive and respiratory syndrome virus Type 1 (PRRSV-1) harbours high genetic diversity and that genetically divergent subtypes 2–4 circulate in this area. In the present study, we compared the pathogenicity of two different PRRSV-1 subtype 2 strains and a strain representing PRRSV-1 subtype 1. Four groups of 8-week-old specific pathogen free pigs were either infected with subtype 2 strain ILI6, subtype 2 strain or BOR59, subtype 1 strain 18794, or mock inoculated. The most pronounced clinical signs were observed in pigs infected with BOR59. Pigs from both subtype 2 strain infected groups exhibited significantly elevated mean body temperatures on DPI 2 compared to the other two groups, the difference remaining significant up to DPI 13 for the BOR59 group, only. The pigs in the latter group also displayed significantly highest levels of early viremia together with the most rapid APP response. Overall, the results indicated that BOR59 strain can be considered a highly pathogenic strain, similarly to subtype 3 strains Lena and SU1-bel, while the virulence of the other subtype 2 strain ILI6 was intermediate between BOR59 and subtype 1 strain.


id: cord-270688-g703hhm4
author: Zhao, Ge
date: 2020-07-11
txt: ./txt/cord-270688-g703hhm4.txt
cache: ./cache/cord-270688-g703hhm4.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0882401020307518?v=s5
doi: 10.1016/j.micpath.2020.104385
summary:
  In order to investigate enterobacteria presence involved in the secondary infections in Porcine Reproductive and Respiratory Syndrome (PRRS) pigs with different viral co-infections, we identified enterobacteria for guiding clinical treatment. Approximately 13 types of bacteria were successfully isolated from lung, spleen, liver, kidney and lymph node samples of different PRRS pigs. Enterobacteria were isolated in 100% of lung, liver and lymph samples from pigs infected with PRRSV alone. In the PRRSV alone infection group, enterobacteria were detected with a 157 100% positive rate in lung, liver and lymph samples, whereas in the co-infection group with 158 more than 3 types of virus species, the isolation rates in lung, liver, kidney and lymph were 159 significantly decreased. Secondary infection with Streptococcus suis serotype 7 increases the 291 virulence of highly pathogenic porcine reproductive and respiratory syndrome virus in pigs Pathogenesis of porcine reproductive and respiratory syndrome virus infection in 322 gnotobiotic pigs

title:
  Identification of enterobacteria in viscera of pigs afflicted with porcine reproductive and respiratory syndrome and other viral co-infections

abstract:
  In order to investigate enterobacteria presence involved in the secondary infections in Porcine Reproductive and Respiratory Syndrome (PRRS) pigs with different viral co-infections, we identified enterobacteria for guiding clinical treatment. Twenty-one diseased pigs were diagnosed with the PRRS virus (PRRSV) and other 7 virus primers by PCR/RT-PCR in the lung and spleen samples. Enterobacteria were isolated using MacConkey agar from 5 visceral samples of PRRS pigs, and identified by 16S rDNA sequencing. PRRSV was positive in 100% of the lung samples and 81.0% of the spleen samples. Seven diseased pigs were diagnosed with only PRRSV infection (33.3%), 7 pigs with PRRSV and 1 or 2 other viruses (33.3%) and 7 pigs with PRRSV and more than 2 types of other viruses (33.3%). PRRSV was more inclined to co-infect pigs with porcine group A rotavirus (PARV) with the co-infection rate of 52.4% (11/21). Approximately 13 types of bacteria were successfully isolated from lung, spleen, liver, kidney and lymph node samples of different PRRS pigs. Enterobacteria were isolated in 100% of lung, liver and lymph samples from pigs infected with PRRSV alone. However, the isolation rates were significantly decreased in the more than 3 viruses co-infection group. Escherichia coli was the most prevalent bacterium, followed by Morganella, Proteus, Shigella, Salmonella, Klebsiella and Aeromonas. Most of the isolated enterobacteria were opportunistic pathogens. Therefore, timely combination with antimicrobial agents is necessary for effective treatment of PRRS-infected pigs.


id: cord-272729-nbgdmavr
title: Ribavirin efficiently suppresses porcine nidovirus replication
author: Kim, Youngnam
date: 2012-10-27
txt: ./txt/cord-272729-nbgdmavr.txt
cache: ./cache/cord-272729-nbgdmavr.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0168170212004078
doi: 10.1016/j.virusres.2012.10.018
summary:
  Investigations into the mechanism of action of ribavirin against PRRSV and PEDV revealed that the addition of guanosine to the ribavirin treatment significantly reversed the antiviral effects, suggesting that depletion of the intracellular GTP pool by inhibiting IMP dehydrogenase may be essential for ribavirin activity. Further experiments revealed that suppression of ribavirin affects post-entry steps of the replication cycle of PRRSV and PEDV, including viral genomic and sg RNA synthesis, viral protein expression, and virus production. Several mechanisms of action for the antiviral activity of ribavirin have been suggested, including a reduction in cellular GTP pools via inosine monophosphate dehydrogenase (IMPDH) inhibition and increased mutation frequency on the virus genome leading to error catastrophe (Graci and Cameron, 2006) . Treatment of cells with ribavirin resulted in significant attenuation of postentry steps during the replication of porcine nidovirus, as determined by lower progeny production, diminished viral protein expression, and decreased synthesis of genomic RNA and sg mRNA.

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine epidemic diarrhea virus (PEDV) are porcine nidoviruses that represent emerging viral pathogens causing heavy economic impacts on the swine industry. Although ribavirin is a well-known antiviral drug against a broad range of both DNA and RNA viruses in vitro, its inhibitory effect and mechanism of action on porcine nidovirus replication remains to be elucidated. Therefore, the present study was conducted to determine whether ribavirin suppresses porcine nidovirus infection. Our results demonstrated that ribavirin treatment dose-dependently inhibited the replication of both nidoviruses. The antiviral activity of ribavirin on porcine nidovirus replication was found to be primarily exerted at early times post-infection. Treatment with ribavirin resulted in marked reduction of viral genomic and subgenomic RNA synthesis, viral protein expression, and progeny virus production in a dose-dependent manner. Investigations into the mechanism of action of ribavirin against PRRSV and PEDV revealed that the addition of guanosine to the ribavirin treatment significantly reversed the antiviral effects, suggesting that depletion of the intracellular GTP pool by inhibiting IMP dehydrogenase may be essential for ribavirin activity. Further sequencing analysis showed that the mutation frequency in ribavirin-treated cells was similar to that in untreated cells, indicating that ribavirin did not induce error-prone replication. Taken together, our data indicate that ribavirin might not only be a good therapeutic agent against porcine nidovirus, but also a potential candidate to be evaluated against other human and animal coronaviruses.


id: cord-275182-cmjfqkjz
title: Vectored vaccines to protect against PRRSV
author: Cruz, Jazmina L.G.
date: 2010-06-25
url: https://api.elsevier.com/content/article/pii/S0168170210002017
doi: 10.1016/j.virusres.2010.06.017
abstract:
  PRRSV is the causative agent of the most important infectious disease affecting swine herds worldwide, producing great economic losses. Commercially available vaccines are only partially effective in protection against PRRSV. Moreover, modified live vaccines may allow virus shedding, and could revert generating virulent phenotypes. Therefore, new efficient vaccines are required. Vaccines based on recombinant virus genomes (virus vectored vaccines) against PRRSV could represent a safe alternative for the generation of modified live vaccines. In this paper, current vectored vaccines to protect against PRRSV are revised, including those based on pseudorabies virus, poxvirus, adenovirus, and virus replicons. Special attention has been provided to the use of transmissible gastroenteritis virus (TGEV) as vector for the expression of PRRSV antigens. This vector has the capability of expressing high levels of heterologous genes, is a potent interferon-α inducer, and presents antigens in mucosal surfaces, eliciting both secretory and systemic immunity. A TGEV derived vector (rTGEV) was generated, expressing PRRSV wild type or modified GP5 and M proteins, described as the main inducers of neutralizing antibodies and cellular immune response, respectively. Protection experiments showed that vaccinated animals developed a faster and stronger humoral immune response than the non-vaccinated ones. Partial protection in challenged animals was observed, as vaccinated pigs showed decreased lung damage when compared with the non-vaccinated ones. Nevertheless, the level of neutralizing antibodies was low, what may explain the limited protection observed. Several strategies are proposed to improve current rTGEV vectors expressing PRRSV antigens.


id: cord-275403-g4rohhtt
author: Bautista, Elida M.
date: 2002-07-05
txt: ./txt/cord-275403-g4rohhtt.txt
cache: ./cache/cord-275403-g4rohhtt.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/12127789/
doi: 10.1006/viro.2002.1495
summary:
  To examine characteristics of putative nonstructural proteins (nsp) encoded in ORF1b, which have been identified by nucleotide similarity to domains of equine arteritis virus, defined genomic regions were cloned and expressed in the pRSET expression system. As initial proof of helicase-like activity, experiments were performed to test the ability of purified PRRSV-14 nsp10 protein to hydrolyze radiolabeled ribonucleotides in the presence or absence of polyribonucleotides. To further analyze the predicted helicase activity of the PRRSV nsp10 protein, experiments were performed using duplex substrates prepared with synthetic oligonucleotides containing single-strand regions at the 3Ј or 5Ј ends and short duplex regions (21 and 24 bp). The 5Ј-to-3Ј orientation of the unwinding activity of the PRRSV helicase was further confirmed in experiments using substrates prepared with in vitro transcribed RNA that contained singlestrand regions at the 5Ј end of both strands and duplex regions of 67 bp (5Ј5ЈDuplex #1) and 85 bp (5Ј5ЈDuplex #2), as shown in Fig. 9B .

title:
  Functional Properties of the Predicted Helicase of Porcine Reproductive and Respiratory Syndrome Virus

abstract:
  Abstract Porcine reproductive and respiratory syndrome virus (PRRSV) is a member of the positive-strand RNA virus family Arteriviridae. Although considerable research has focused on this important pathogen, little is known about the function of most PRRSV proteins. To examine characteristics of putative nonstructural proteins (nsp) encoded in ORF1b, which have been identified by nucleotide similarity to domains of equine arteritis virus, defined genomic regions were cloned and expressed in the pRSET expression system. One region, nsp10, encoded a protein with a putative helicase domain and was further examined for functional helicase-like activities. PRRSV nsp10 was found to possess a thermolabile and pH-sensitive NTPase activity that was modulated by polynucleotides and to unwind dsRNA in a 5′ to 3′ polarity. These results provide the first evidence of the functional properties of PRRSV helicase and further support the finding that nidovirus helicases possess properties that distinguish them from other viral helicases.


id: cord-275413-e2rhioty
title: The interaction between PRRSV and the late gestation pig fetus
author: Rowland, Raymond R.R.
date: 2010-09-09
url: https://www.ncbi.nlm.nih.gov/pubmed/20832434/
doi: 10.1016/j.virusres.2010.09.001
abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) crosses the placenta during late gestation and productively infects the fetus. Virus replication and cytokine responses were measured in tissues of fetuses recovered at 109–112 days of gestation, just prior to parturition. At the time of recovery, gross anatomical abnormalities were evident in both infected and non-infected fetuses from the infected dams. Virus isolation and immunohistochemistry identified the thymus as the primary site of virus replication. Steady state RT-PCR amplification of inflammatory, Th1 and Th2 cytokines, showed elevated IFN-γ and TNF-α mRNAs in tissues from infected fetuses, which corresponded to elevated cytokine proteins in serum but not amniotic fluid. Further evidence for induction of immunity was found in the hyperplastic response of lymph nodes, which included the development of germinal centers occupied CDw75+ B cells. Collectively, these data support the notion that the immunocompetent fetus is capable of initiating an antiviral response, which is compartmentalized within the infected fetus. Furthermore, fetal pathology may not be a direct result of virus replication in the fetus.


id: cord-275570-i9fw0afj
title: Molecular Research on Emerging Viruses: Evolution, Diagnostics, Pathogenesis, and Therapeutics
author: Lau, Susanna K. P.
date: 2018-01-30
url: https://doi.org/10.3390/ijms19020398
doi: 10.3390/ijms19020398
abstract:
  Viruses are increasingly recognized as emerging infectious disease agents in both humans and animals.[...].


id: cord-280578-4yxda0mf
title: Molecular cloning, expression, purification and crystallographic analysis of PRRSV 3CL protease
author: Tian, Xinsheng
date: 2007-07-28
txt: ./txt/cord-280578-4yxda0mf.txt
cache: ./cache/cord-280578-4yxda0mf.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/17671377/
doi: 10.1107/s1744309107033234
summary:
  Viruses of the order Nidovirales regulate their genome expression by synthesizing two multidomain precursor polyproteins that are subsequently cleaved into functional viral proteins mainly by the 3CL protease (den Boon et al., 1991; Birtley et al., 2005; Snijder et al., 1996; van Aken et al., 2006) . The amplified DNA fragment encoding the PRRSV 3CL protease was inserted into the GST-fusion expression vector pGEX-6p-1 (GE Healthcare) with SmaI/XhoI sites (introduced by PCR primers). For protein expression, the plasmid was transformed into Escherichia coli strain BL21 (DE3) competent cells and the single colony was inoculated into Luria-Bertani (LB) medium with 50 mg l À1 ampicillin (Sigma, USA) at 310 K for overnight growth. For crystallization, the purified protein was concentrated to approximately 20 mg ml À1 and the buffer was exchanged to 10 mM Tris-HCl, 10 mM NaCl, 1 mM EDTA, 1 mM DTT pH 7.5.

abstract:
  3CL protease, a viral chymotrypsin-like proteolytic enzyme, plays a pivotal role in the transcription and replication machinery of many RNA viruses, including porcine reproductive and respiratory syndrome virus (PRRSV). In this study, the full-length 3CL protease from PRRSV was cloned and overexpressed in Escherichia coli. Crystallization experiments yielded crystals that diffracted to 2.1 Å resolution and belong to space group C2, with unit-cell parameters a = 112.31, b = 48.34, c = 42.88 Å, β = 109.83°. The Matthews coefficient and the solvent content were calculated to be 2.49 Å(3) Da(−1) and 50.61%, respectively, for one molecule in the asymmetric unit.


id: cord-281309-c9y7m5do
author: Guo, Baoqing
date: 2013-01-20
txt: ./txt/cord-281309-c9y7m5do.txt
cache: ./cache/cord-281309-c9y7m5do.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0042682212004540
doi: 10.1016/j.virol.2012.09.013
summary:
  We found that this HP-PRRSV strain caused extreme morbidity, as was seen in Asia, but novel to this study, resulted in up to 100x higher abundance of circulating virus when compared to VR-2332, caused extremely exacerbated thymic atrophy such that the thymus was often difficult to discern, and the host response was assessed in comparison to animals infected with strain VR-2332 for the first time by a swine protein array including 5 innate and 5 adaptive cytokines in serum, bronchoalveolar lavage fluid and lymph nodes. It was demonstrated that infection with a highly pathogenic strain of PRRSV elicited a significant elevation of all adaptive immunity cytokines measured in BALF, as well as a majority of these cytokines in serum and TBLN homogenates of the same groups of pigs.

title:
  Experimental infection of United States swine with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus

abstract:
  The pathogenesis of Type 2 highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) in 10-week old swine in the United States was investigated. rJXwn06, rescued from an infectious clone of Chinese HP-PRRSV, replicated in swine with at least 100-fold increased kinetics over U.S. strain VR-2332. rJXwn06 caused significant weight loss, exacerbated disease due to bacterial sepsis and more severe histopathological lung lesions in pigs exposed to HP-PRRSV than to those infected with VR-2332. Novel findings include identification of bacterial species present, the degree of thymic atrophy seen, and the inclusion of contact animals that highlighted the ability of HP-PRRSV to rapidly transmit between animals. Furthermore, comprehensive detailed cytokine analysis of serum, bronchoalveolar lavage fluid, and tracheobronchial lymph node tissue homogenate revealed a striking elevation in levels of cytokines associated with both innate and adaptive immunity in HP-PRRSV infected swine, and showed that contact swine differed in the degree of cytokine response.


id: cord-281676-yy5etfek
author: Dwivedi, Varun
date: 2011-05-23
txt: ./txt/cord-281676-yy5etfek.txt
cache: ./cache/cord-281676-yy5etfek.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0264410X11003586
doi: 10.1016/j.vaccine.2011.03.006
summary:
  Consistent with the reduced lung lesions and viremia, a significantly increased frequency of IFN-␥Table 1 Frequency of immune cells in pigs inoculated intranasally with mock (no vaccination and no challenge), unvaccinated (n = 9) or vaccinated with PRRS-MLV+ Mtb WCL (n = 9) and then challenged with PRRSV MN184. Evaluation of the frequency of various immune cells at both mucosal (lung and TBLN MNC) and systemic sites (PBMC) in vaccinated and virulent PRRSV challenged pigs is important for associating cytokine responses. In our study, a consistently reduced frequency of Tregs in the lungs, blood, and TBLN of pigs vaccinated intranasally with PRRS-MLV+ Mtb WCL was detected which was associated with reduced secretion of both the immunosuppressive cytokines, IL-10 and TGF-␤. Intranasal delivery of whole cell lysate of Mycobacterium tuberculosis induces protective immune responses to a modified live porcine reproductive and respiratory syndrome virus vaccine in pigs

title:
  Cross-protective immunity to porcine reproductive and respiratory syndrome virus by intranasal delivery of a live virus vaccine with a potent adjuvant

abstract:
  Abstract Porcine reproductive and respiratory syndrome (PRRS) is an immunosuppressive chronic respiratory viral disease of pigs that is responsible for major economic losses to the swine industry worldwide. The efficacy of parenteral administration of widely used modified live virus PRRS vaccine (PRRS-MLV) against genetically divergent PRRSV strains remains questionable. Therefore, we evaluated an alternate and proven mucosal immunization approach by intranasal delivery of PRRS-MLV (strain VR2332) with a potent adjuvant to elicit cross-protective immunity against a heterologous PRRSV (strain MN184). Mycobacterium tuberculosis whole cell lysate (Mtb WCL) was chosen as a potent mucosal adjuvant due to its Th1 biased immune response to PRRS-MLV. Unvaccinated pigs challenged with MN184 had clinical PRRS with severe lung pathology; however, vaccinated (PRRS-MLV+ Mtb WCL) pigs challenged with MN184 were apparently healthy. There was a significant increase in the body weight gain in vaccinated compared to unvaccinated PRRSV challenged pigs. Vaccinated compared to unvaccinated, virus-challenged pigs had reduced lung pathology associated with enhanced PRRSV neutralizing antibody titers and reduced viremia. Immunologically, an increased frequency of Th cells, Th/memory cells, γδ T cells, dendritic cells, and activated Th cells and a reduced frequency of T-regulatory cells were detected at both mucosal and systemic sites. Further, reduced secretion of immunosuppressive cytokines (IL-10 and TGF-β) and upregulation of the Th1 cytokine IFN-γ in blood and lungs were detected in mucosally vaccinated, PRRSV-challenged pigs. In conclusion, intranasal immunization of pigs with PRRS-MLV administered with Mtb WCL generated effective cross-protective immunity against PRRSV.


id: cord-282113-sed5xyte
author: Zheng, Hao
date: 2010-10-15
txt: ./txt/cord-282113-sed5xyte.txt
cache: ./cache/cord-282113-sed5xyte.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/20728481/
doi: 10.1016/j.jbiotec.2010.08.009
summary:
  In this paper, we have used porcine reproductive and respiratory syndrome virus (PRRSV) as a model virus to address whether infectious mammalian virus particles can be generated in insect cells from recombinant baculovirus. To investigate whether PRRSV particles were generated following infection of insect cells with the recombinant baculovirus, sf9 cells were infected with AcAPRRS and supernatants were harvested 7 days later. We report that infection of insect sf9 cells with the recombinant baculovirus AcAPRRS led to the synthesis of PRRSV proteins and the culture supernatant contained particles that were morphologically indistinguishable from PRRSV virions. In this study, we have demonstrated that a recombinant baculovirus carrying PRRSV genomic cDNA was able to generate infectious PRRSV following transduction of mammalian cells that are themselves refractory to infection with PRRSV in vitro. When the recombinant baculovirus was inoculated onto insect sf9 cells or mammalian Vero and BHK-21 cells, infectious PRRSV virions were generated.

title:
  Baculovirus expression of cloned porcine arterivirus generates infectious particles in both insect and mammalian cells

abstract:
  Studies on several viral pathogens have been hampered by the lack of appropriate in vitro systems for their propagation and amplification. Porcine reproductive and respiratory syndrome virus (PRRSV), an arterivirus containing a single-stranded positive-sense RNA genome (∼15 kb), was served as a model virus and its genomic cDNA was recombinated into baculovirus. We investigated whether infectious virus particles could be generated by expression of the full-length cloned genome from the modified baculovirus vector. The recombinant baculovirus, AcAPRRS, was used to infect sf9 cells. Immunofluorescence assay demonstrated the presence of PRRSV nonstructural protein (nsp) 2 and nucleocapsid (N) protein and electron microscopy revealed PRRSV particles in the culture supernatant. Infectious PRRSV particles were also produced in susceptible MARC-145 cells inoculated with AcAPRRS, and the growth characteristics of the PRRSV generated were similar to those of the parental PRRSV strain. Infectious PRRSV particles were also generated following AcAPRRS transduction of BHK-21 cells and Vero cells that are not sensitive to PRRSV. Titers of PRRSV obtained from BHK-21 and Vero cells were up to 10(4.05) TCID(50)/ml. These findings open a new route to the propagation of the virus in vitro and will be of utility in vaccine development.


id: cord-282242-5tkhjiwl
author: Gómez-Laguna, J.
date: 2009-08-19
txt: ./txt/cord-282242-5tkhjiwl.txt
cache: ./cache/cord-282242-5tkhjiwl.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1016/j.jcpa.2009.07.004
doi: 10.1016/j.jcpa.2009.07.004
summary:
  title: Cytokine Expression by Macrophages in the Lung of Pigs Infected with the Porcine Reproductive and Respiratory Syndrome Virus The aim of the present study was to characterize the production of cytokines by subpopulations of pulmonary macrophages in pigs infected by the PRRS virus (PRRSV). Several studies have examined the role of cytokines in the pathogenesis of PRRS (Van Reeth and Nauwynck, 2000) ; however, it is not clear how cytokines participate in macrophage activation during PRRSV infection or how they regulate development of the immune response to the virus. The expression of IFN-g by macrophages and lymphocytes has been previously reported in the lung of PRRSV-infected pigs (Thanawongnuwech et al., 2003) . Therefore, the expression of IL-10 observed in the present study might be responsible for reduced expression of cytokines such as IFN-a, IFN-g, IL-12p40 and TNF-a, that in turn may impair prolonged viral replication in the lung of infected animals.

title:
  Cytokine Expression by Macrophages in the Lung of Pigs Infected with the Porcine Reproductive and Respiratory Syndrome Virus

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) is caused by a virus that predominantly replicates in alveolar macrophages. The aim of the present study was to characterize the production of cytokines by subpopulations of pulmonary macrophages in pigs infected by the PRRS virus (PRRSV). Expression of interleukin (IL) 1α, IL-6 and tumour necrosis factor (TNF)-α correlated with the severity of pulmonary pathology and the numbers of pulmonary macrophages. Significant correlations were observed between PRRSV infection and the expression of IL-10, between the expression of IL-12p40 and interferon (IFN)-γ, and between the expression of TNF-α and IFN-γ. These findings suggest that PRRSV modulates the immune response by the up-regulation of IL-10, which may in turn reduce expression of cytokines involved in viral clearance (e.g. IFN-α, IFN-γ, IL-12p40 and TNF-α). The results also suggest that expression of IFN-γ is stimulated by IL-12p40 and TNF-α, but not by IFN-α. All of these cytokines were expressed mainly by septal macrophages with weaker expression by alveolar macrophages, lymphocytes and neutrophils. There appears to be differential activation of septal and alveolar macrophages in PRRSV infection, with septal macrophages being the major source of cytokines.


id: cord-283689-dzin12qb
title: Involvement of PRRSV NSP3 and NSP5 in the autophagy process
author: Zhang, Wei
date: 2019-01-28
url: https://www.ncbi.nlm.nih.gov/pubmed/30691473/
doi: 10.1186/s12985-019-1116-x
abstract:
  BACKGROUND: Autophagy is an essential process in eukaryotic cells in which autophagosomes form to deliver cellular organelles and long-lived proteins to lysosomes for degradation. Many studies have recently identified the regulatory mechanisms involved in the interaction between viral infection and autophagy. METHODS: LC3 turnover and the proteins in the endoplasmic reticulum (ER) stress pathway were investigated using western blot analysis. The formation and degradation of autophagosomes were detected using immunofluorescence staining. RESULTS: Autophagy was activated by porcine reproductive and respiratory syndrome virus (PRRSV) NSP3, NSP5 and NSP9, which are two transmembrane proteins and an RNA-dependent RNA polymerase, respectively. The formation of autophagosomes was induced by NSP3 and NSP5 and developed from the ER; the fusion of these autophagosomes with lysosomes was limited. Although NSP3 and NSP5 are ER transmembrane proteins, these proteins did not activate the ER stress signaling pathways. In addition, the cytoplasmic domain of NSP3 plays a pivotal role in activating autophagy. CONCLUSIONS: The data presented in this study reveal an important relationship between PRRSV NSPs and autophagy and provide new insights that improve our understanding of the involvement of PRRSV NSPs in the autophagy process. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12985-019-1116-x) contains supplementary material, which is available to authorized users.


id: cord-284076-087oltss
author: Patel, Deendayal
date: 2007-10-04
url: https://www.ncbi.nlm.nih.gov/pubmed/17959259/
doi: 10.1016/j.antiviral.2007.09.002
title:
  Peptide-conjugated morpholino oligomers inhibit porcine reproductive and respiratory syndrome virus replication

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) has been devastating the global swine industry for more than a decade, and current strategies to control PRRS are inadequate. In this study we characterized the inhibition of PRRS virus (PRRSV) replication by antisense phosphorodiamidate morpholino oligomers (PMO). Of 12 peptide-conjugated PMO (PPMO), four were found to be highly effective at inhibiting PRRSV replication in cell culture in a dose-dependant and sequence-specific manner. PPMO 5UP2 and 5HP are complementary to sequence in the 5′ end of the PRRSV genome, and 6P1 and 7P1 to sequence in the translation initiation regions of ORF6 and ORF7, respectively. Treatment of cells with 5UP2 or 5HP caused a 4.5 log(10) reduction in PRRSV yield, compared to a control PPMO. Combination of 6P1 and 7P1 led to higher level reduction than 6P1 or 7P1 alone. 5UP2, 5HP, and a combination of 6P1 and 7P1 inhibited PRRSV replication in porcine alveolar macrophages and protected the cells from PRRSV-induced cytopathic effect. Northern blot and real-time RT-PCR results demonstrated that the effective PPMO led to a reduction of PRRSV RNA level. 5UP2 and 5HP inhibited virus replication of 10 other strains of PRRSV. Results from this study suggest potential applications of PPMO for PRRS control.


id: cord-285746-ndrja7os
author: Arjin, Chaiwat
date: 2020-03-30
url: https://doi.org/10.1186/s12917-020-02320-8
doi: 10.1186/s12917-020-02320-8
title:
  In vitro screening antiviral activity of Thai medicinal plants against porcine reproductive and respiratory syndrome virus

abstract:
  BACKGROUND: Porcine reproductive and respiratory syndrome (PRRS) caused by PRRS virus (PRRSV) results in economic losses in the swine industry globally. Several studies have investigated the use of plant extracts in the prevention and control of PRRS outbreaks. Thai medicinal plants may be useful for treating PRRSV infection in pigs. Therefore, we investigated the in vitro anti-PRRSV and antioxidant properties of seven Thai medicinal plants: Caesalpinia sappan Linn., Garcinia mangostana Linn., Houttuynia cordata, Perilla frutescens, Clinacanthus nutans, Phyllanthus emblica, and Tiliacora triandra. RESULTS: Using antiviral screening, we observed that T. triandra extract strongly inhibited PRRSV infectivity in MARC-145 cells [virus titer 3.5 median tissue culture infective dose (TCID(50))/ml (log10)] at 24 h post-infection, whereas C. sappan extract strongly inhibited PRRSV replication [virus titer 2.5 TCID(50)/ml (log10)] at 72 h post-infection. C. sappan extract had the highest total phenolic content [220.52 mM gallic acid equivalent/g] and lowest half-maximal inhibitory concentration [1.17 mg/ml in 2,2-diphenyl-1-picrylhydrazyl and 2.58 mg/ml in 2,2-azino-bis (3-ethylbenzothiazo-line-6-sulfonic acid) diammonium salt]. CONCLUSION: T. triandra extract could inhibit PRRSV infectivity, whereas C. sappan extract was the most effective in inhibiting PRRSV replication in MARC-145 cells. This study elucidates the antiviral activities of Thai medicinal plant extracts in vivo. The results promise that Thai medicinal plant extracts, particularly T. triandra and C. sappan extracts, can be developed into pharmaceutical drugs for the prevention of PRRS in pigs.


id: cord-288669-46tkedw7
author: Lee, Changhee
date: 2006-11-10
url: https://api.elsevier.com/content/article/pii/S0042682206004521
doi: 10.1016/j.virol.2006.07.013
title:
  The small envelope protein of porcine reproductive and respiratory syndrome virus possesses ion channel protein-like properties

abstract:
  The small envelope (E) protein of porcine reproductive and respiratory syndrome virus (PRRSV) is a hydrophobic 73 amino acid protein encoded in the internal open reading frame (ORF) of the bicistronic mRNA2. As a first step towards understanding the biological role of E protein during PRRSV replication, E gene expression was blocked in a full-length infectious clone by mutating the ATG translational initiation to GTG, such that the full-length mutant genomic clone was unable to synthesize the E protein. DNA transfection of PRRSV-susceptible cells with the E gene knocked-out genomic clone showed the absence of virus infectivity. P129-ΔE-transfected cells however produced virion particles in the culture supernatant, and these particles contained viral genomic RNA, demonstrating that the E protein is essential for PRRSV infection but dispensable for virion assembly. Electron microscopy suggests that the P129-ΔE virions assembled in the absence of E had a similar appearance to the wild-type particles. Strand-specific RT-PCR demonstrated that the E protein-negative, non-infectious P129-ΔE virus particles were able to enter cells but further steps of replication were interrupted. The entry of PRRSV has been suggested to be via receptor-mediated endocytosis, and lysomotropic basic compounds and known ion-channel blocking agents both inhibited PRRSV replication effectively during the uncoating process. The expression of E protein in Escherichia coli-mediated cell growth arrests and increased the membrane permeability. Cross-linking experiments in cells infected with PRRSV or transfected with E gene showed that the E protein was able to form homo-oligomers. Taken together, our data suggest that the PRRSV E protein is likely an ion-channel protein embedded in the viral envelope and facilitates uncoating of virus and release of the genome in the cytoplasm.


id: cord-289152-w5ynbewh
title: Porcine arterivirus activates the NF-κB pathway through IκB degradation
author: Lee, Sang-Myeong
date: 2005-11-10
txt: ./txt/cord-289152-w5ynbewh.txt
cache: ./cache/cord-289152-w5ynbewh.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/16129468/
doi: 10.1016/j.virol.2005.07.034
summary:
  In porcine reproductive and respiratory syndrome virus (PRRSV)-infected cells, NF-κB activation was characterized by translocation of NF-κB from the cytoplasm to the nucleus, increased DNA binding activity, and NF-κB-regulated gene expression. Taken together, these results demonstrated that PRRSV induces nuclear translocation of NF-nB followed by increased DNA binding activity of NF-nB both in MARC-145 cells and PAM cultures. To determine if NF-nB activation by PRRSV was dependent on InBa degradation in MARC-145 cells, the NF-nB pathway was blocked by using an adenovirus vector expressing a dominant negative form of InBa (Ad-InBaDN) which lacks both constitutive (Barroga et al., 1995) and inducible (Brown et al., 1995) phosphorylation sites. This study showed that PRRSV infection resulted in increased nuclear translocation of NF-nB and increased DNA binding activity both in MARC-145 cells and PAM cultures.

abstract:
  Nuclear factor-kappaB (NF-κB) is a critical regulator of innate and adaptive immune function as well as cell proliferation and survival. The present study demonstrated for the first time that a virus belonging to the Arteriviridae family activates NF-κB in MARC-145 cells and alveolar macrophages. In porcine reproductive and respiratory syndrome virus (PRRSV)-infected cells, NF-κB activation was characterized by translocation of NF-κB from the cytoplasm to the nucleus, increased DNA binding activity, and NF-κB-regulated gene expression. NF-κB activation was increased as PRRSV infection progressed and in a viral dose-dependent manner. UV-inactivation of PRRSV significantly reduced the level of NF-κB activation. Degradation of IκB protein was detected late in PRRSV infection, and overexpression of the dominant negative form of IκBα (IκBαDN) significantly suppressed NF-κB activation induced by PRRSV. However, IκBαDN did not affect viral replication and viral cytopathic effect. PRRSV infection induced oxidative stress in cells by generating reactive oxygen species (ROS), and antioxidants inhibited NF-κB DNA binding activity in PRRSV-infected cells, suggesting ROS as a mechanism by which NF-κB was activated by PRRSV infection. Moreover, NF-κB-dependent expression of matrix metalloproteinase (MMP)-2 and MMP-9 was observed in PRRSV-infected cells, an observation which implies that NF-κB activation is a biologically significant aspect of PRRSV pathogenesis. The results presented here provide a basis for understanding molecular pathways of pathology and immune evasion associated with disease caused by PRRSV.


id: cord-290775-w8ukokl7
author: Tian, Xinsheng
date: 2009-10-02
url: https://www.ncbi.nlm.nih.gov/pubmed/19646449/
doi: 10.1016/j.jmb.2009.07.062
title:
  Structure and Cleavage Specificity of the Chymotrypsin-Like Serine Protease (3CLSP/nsp4) of Porcine Reproductive and Respiratory Syndrome Virus (PRRSV)

abstract:
  Summary Biogenesis and replication of the porcine reproductive and respiratory syndrome virus (PRRSV) include the crucial step of replicative polyprotein processing by self-encoded proteases. Whole genome bioinformatics analysis suggests that nonstructural protein 4 (nsp4) is a 3C-like serine protease (3CLSP), responsible for most of the nonstructural protein processing. The gene encoding this protease was cloned and expressed in Escherichia coli in order to confirm this prediction. The purified protein was crystallized, and the structure was solved at 1.9 Å resolution. In addition, the crystal structure of the Ser118Ala mutant was determined at 2.0 Å resolution. The monomeric enzyme folds into three domains, similar to that of the homologous protease of equine arteritis virus, which, like PRRSV, is a member of the family Arteriviridae in the order of Nidovirales. The active site of the PRRSV 3CLSP is located between domains I and II and harbors a canonical catalytic triad comprising Ser118, His39, and Asp64. The structure also shows an atypical oxyanion hole and a partially collapsed S1 specificity pocket. The proteolytic activity of the purified protein was assessed in vitro. Three sites joining nonstructural protein domains in the PRRSV replicative polyprotein are confirmed to be processed by the enzyme. Two of them, the nsp3/nsp4 and nsp11/nsp12 junctions, are shown to be cleaved in trans, while cis cleavage is demonstrated for the nsp4/nsp5 linker. Thus, we provide structural evidence as well as enzymatic proof of the nsp4 protein being a functional 3CLSP. We also show that the enzyme has a strong preference for glutamic acid at the P1 position of the substrate.


id: cord-291192-wm2eyaam
title: Antigenic structures stably expressed by recombinant TGEV-derived vectors
author: Becares, Martina
date: 2014-08-09
url: https://api.elsevier.com/content/article/pii/S0042682214003353
doi: 10.1016/j.virol.2014.07.027
abstract:
  Coronaviruses (CoVs) are positive-stranded RNA viruses with potential as immunization vectors, expressing high levels of heterologous genes and eliciting both secretory and systemic immune responses. Nevertheless, its high recombination rate may result in the loss of the full-length foreign gene, limiting their use as vectors. Transmissible gastroenteritis virus (TGEV) was engineered to express porcine reproductive and respiratory syndrome virus (PRRSV) small protein domains, as a strategy to improve heterologous gene stability. After serial passage in tissue cultures, stable expression of small PRRSV protein antigenic domains was achieved. Therefore, size reduction of the heterologous genes inserted in CoV-derived vectors led to the stable expression of antigenic domains. Immunization of piglets with these TGEV vectors led to partial protection against a challenge with a virulent PRRSV strain, as immunized animals showed reduced clinical signs and lung damage. Further improvement of TGEV-derived vectors will require the engineering of vectors with decreased recombination rate.


id: cord-291962-rp172ugk
author: Jing, Huiyuan
date: 2019-07-15
txt: ./txt/cord-291962-rp172ugk.txt
cache: ./cache/cord-291962-rp172ugk.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0168170219302485
doi: 10.1016/j.virusres.2019.05.011
summary:
  title: Nucleotide-binding oligomerization domain-like receptor X1 restricts porcine reproductive and respiratory syndrome virus-2 replication by interacting with viral Nsp9 To test this, increasing dose of NLRX1 was transfected into Marc-145 cells followed by PRRSV infection, qPCR was then performed to test the total viral RNA levels. On the other hand, recent literature indicated that the interaction of Nsp9 with SUMO E2 conjugating enzyme Ubc9 and cellular protein interleukin-2 enhancer binding factor 2 (ILF2) through its RdRp domain resulted in a significantly decrease of virus titers, indicating that cells utilize host antiviral factors as defense mechanisms to limit PRRSV infection Wen et al., 2017) . An intracellularly expressed Nsp9-specific nanobody in MARC-145 cells inhibits porcine reproductive and respiratory syndrome virus replication Porcine reproductive and respiratory syndrome virus nucleocapsid protein interacts with Nsp9 and cellular DHX9 to regulate viral RNA synthesis The DEADbox RNA helicase 5 positively regulates the replication of porcine reproductive and respiratory syndrome virus by interacting with viral Nsp9 in vitro

title:
  Nucleotide-binding oligomerization domain-like receptor X1 restricts porcine reproductive and respiratory syndrome virus-2 replication by interacting with viral Nsp9

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) causes one of the most economically important diseases of swine worldwide. Current antiviral strategies provide only limited protection. Nucleotide-binding oligomerization domain-like receptor (NLR) X1 is unique among NLR proteins in its functions as a pro-viral or antiviral factor to different viral infections. To date, the impact of NLRX1 on PRRSV infection remains unclear. In this study, we found that PRRSV infection promoted the expression of NLRX1 gene. In turn, ectopic expression of NLRX1 inhibited PRRSV replication in Marc-145 cells, whereas knockdown of NLRX1 enhanced PRRSV propagation in porcine alveolar macrophages (PAMs). Mechanistically, NLRX1 was revealed to impair intracellular viral subgenomic RNAs accumulation. Finally, Mutagenic analyses indicated that the LRR (leucine-rich repeats) domain of NLRX1 interacted with PRRSV Nonstructural Protein 9 (Nsp9) RdRp (RNA-dependent RNA Polymerase) domain and was necessary for antiviral activity. Thus, our study establishes the role of NLRX1 as a new host restriction factor in PRRSV infection.


id: cord-293768-uijc6qdo
title: Immunity to PRRSV: Double-edged sword
author: Molitor, T. W.
date: 1997-04-30
url: https://www.ncbi.nlm.nih.gov/pubmed/9220622/
doi: 10.1016/s0378-1135(96)01327-2
abstract:
  Abstract The immune system is a double-edged sword for porcine reproductive and respiratory syndrome virus (PRRSV) infection. On one edge PRRSV has a predilection for immune cells and the disease manifestations can be linked directly to changes in the immune system. PRRSV appears to replicate extensively, if not exclusively, in cells of the immune lineage, notably macrophages; the direct replication of which may lead to immunosuppression, precipitate secondary infection and/or mediate disease. On the other edge, the virus stimulates immunity post-infection that protects an animal from re-infection. A vast array of structural and functionally distinct antibody specific to PRRSV are generated following infection or vaccination. Discrete populations of functional antibodies appear at different times and possibly reflect reactivity to different PRRSV polypeptides. Cell-mediated immune responses specific to PRRSV can be detected in various exposed pigs as well. Thus, the immune system appears to be intimately involved in both the disease process and protection from disease. It is unclear at this state of understanding what immune compartment provides protective immunity. Is it humoral (i.e. antibodies), selective functionally distinct populations of antibodies specific for selected PRRSV polypeptides or is cellular immunity essential for protection, or both. This review will attempt to summarize the current state of knowledge of the complex interaction of the immune system and PRRSV.


id: cord-298131-zolwjl9u
author: Xiao, Shuqi
date: 2010-06-29
txt: ./txt/cord-298131-zolwjl9u.txt
cache: ./cache/cord-298131-zolwjl9u.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/20614006/
doi: 10.1371/journal.pone.0011377
summary:
  Upregulation expression of virus-induced pro-inflammatory cytokines, chemokines, adhesion molecules and inflammatory enzymes and inflammatory cells, antibodies, complement activation were likely to result in the development of inflammatory responses during N-PRRSV infection processes. To investigate the regulation of the host response to the N-PRRSV virus, we considered the global gene expression profiles in lungs using Solexa/Illumina''s DGE system, a tag-based transcriptome sequencing method. From the data presented in the paper, a model for the relationship between pulmonary gene expression profiles and infection pathology can be surmised in Figure 7 , N-PRRSV virus replicates and spreads by subverting host innate immune response and hijacking host lipid metabolism as well as inducing an antiapoptotic and anti-inflammatory state, as indicated by suppression expression of SPI IFN, IFN-a, down-regulation expression of proapoptotic genes for BAK, APR-1, SARP3, high levels expression of genes involved in lipid metabolism, such as APOE, LDLB, PIK3C3, anti-apoptotic genes for MCL1, BCL2A1, CHFR, ADM, NFKB, IL10, and anti-inflammatory molecule PGE2 as well as CD163.

title:
  Understanding PRRSV Infection in Porcine Lung Based on Genome-Wide Transcriptome Response Identified by Deep Sequencing

abstract:
  Porcine reproductive and respiratory syndrome (PRRS) has been one of the most economically important diseases affecting swine industry worldwide and causes great economic losses each year. PRRS virus (PRRSV) replicates mainly in porcine alveolar macrophages (PAMs) and dendritic cells (DCs) and develops persistent infections, antibody-dependent enhancement (ADE), interstitial pneumonia and immunosuppression. But the molecular mechanisms of PRRSV infection still are poorly understood. Here we report on the first genome-wide host transcriptional responses to classical North American type PRRSV (N-PRRSV) strain CH 1a infection using Solexa/Illumina's digital gene expression (DGE) system, a tag-based high-throughput transcriptome sequencing method, and analyse systematically the relationship between pulmonary gene expression profiles after N-PRRSV infection and infection pathology. Our results suggest that N-PRRSV appeared to utilize multiple strategies for its replication and spread in infected pigs, including subverting host innate immune response, inducing an anti-apoptotic and anti-inflammatory state as well as developing ADE. Upregulation expression of virus-induced pro-inflammatory cytokines, chemokines, adhesion molecules and inflammatory enzymes and inflammatory cells, antibodies, complement activation were likely to result in the development of inflammatory responses during N-PRRSV infection processes. N-PRRSV-induced immunosuppression might be mediated by apoptosis of infected cells, which caused depletion of immune cells and induced an anti-inflammatory cytokine response in which they were unable to eradicate the primary infection. Our systems analysis will benefit for better understanding the molecular pathogenesis of N-PRRSV infection, developing novel antiviral therapies and identifying genetic components for swine resistance/susceptibility to PRRS.


id: cord-299038-e0nsol3y
title: Siglecs at the Host–Pathogen Interface
author: Chang, Yung-Chi
date: 2020-03-10
txt: ./txt/cord-299038-e0nsol3y.txt
cache: ./cache/cord-299038-e0nsol3y.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/32152948/
doi: 10.1007/978-981-15-1580-4_8
summary:
  Conversely, Siglec-1 is a macrophage phagocytic receptor that engages GBS and other sialylated bacteria to promote effective phagocytosis and antigen presentation for the adaptive immune response, whereas certain viruses and parasites use Siglec-1 to gain entry to immune cells as a proximal step in the infectious process. The interplay between a particular sialylated human pathogen, group B Streptococcus (GBS), and host immune responses serves as a good first example to illustrate the role of Siglecs and bacterial expression of Sia in the pathogenesis of infection. Importantly, in addition to Sia-dependent Siglec engagement, certain GBS strains can use the surface-anchored β protein to bind human Siglec-5, another inhibitory Siglec preferentially expressed on macrophages and neutrophils. Loss of Siglec-1 expression not only affected the macrophage sampling and trapping capabilities but also the production of anti-GBS antibodies, suggesting a key role in optimization of antigen presentation and subsequent adaptive immune response against sialylated pathogens (Chang et al.

abstract:
  Siglecs are sialic acid (Sia) recognizing immunoglobulin-like receptors expressed on the surface of all the major leukocyte lineages in mammals. Siglecs recognize ubiquitous Sia epitopes on various glycoconjugates in the cell glycocalyx and transduce signals to regulate immunological and inflammatory activities of these cells. The subset known as CD33-related Siglecs is principally inhibitory receptors that suppress leukocyte activation, and recent research has shown that a number of bacterial pathogens use Sia mimicry to engage these Siglecs as an immune evasion strategy. Conversely, Siglec-1 is a macrophage phagocytic receptor that engages GBS and other sialylated bacteria to promote effective phagocytosis and antigen presentation for the adaptive immune response, whereas certain viruses and parasites use Siglec-1 to gain entry to immune cells as a proximal step in the infectious process. Siglecs are positioned in crosstalk with other host innate immune sensing pathways to modulate the immune response to infection in complex ways. This chapter summarizes the current understanding of Siglecs at the host–pathogen interface, a field of study expanding in breadth and medical importance, and which provides potential targets for immune-based anti-infective strategies.


id: cord-299721-gm6nx84a
author: Franzo, Giovanni
date: 2014-12-19
url: https://api.elsevier.com/content/article/pii/S0168170214003335
doi: 10.1016/j.virusres.2014.08.005
title:
  Observation of high recombination occurrence of Porcine Reproductive and Respiratory Syndrome Virus in field condition

abstract:
  Abstract Recombination in Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) is a well-documented phenomenon. A high recombination frequency has been reported in experimental conditions both in vitro and in vivo, and its role in driving viral evolution has been postulated by several authors. However field evidences are rare, mainly obtained from large-scale sampling and typically represented by single sequences rather than by groups of circulating “recombinant progenies”. The present work was aimed to investigate the gray area between experimental studies and large-scale epidemiological investigations. The study was performed on ORF5, ORF7 and concatenated sequences obtained in our laboratory or available in GenBank collected between 2009 and 2012 in northern Italy. Six independent recombinant strains out of 66 concatenated sequences (∼9%) were found, demonstrating a high recombination frequency respect to previous field studies but comparable to in vitro experiments. In silico analysis let speculate that this new strain displayed physicochemical features diverse enough to potentially alter its immunological properties. Taken altogether, the results of our study support previous experimental evidences that depict PRRSV to be extremely prone to recombination. The limited temporal and geographical spread of recombinant strains however states in favor of a limited fitness of the recombinant progeny compared to parental strains and the marginal role of this phenomenon in PRRSV evolution.


id: cord-299751-2drhoz70
author: Tabynov, Kairat
date: 2016-08-30
txt: ./txt/cord-299751-2drhoz70.txt
cache: ./cache/cord-299751-2drhoz70.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1016/j.vetmic.2016.06.014
doi: 10.1016/j.vetmic.2016.06.014
summary:
  The efficacy of a novel BEI-inactivated porcine reproductive and respiratory syndrome virus (PRRSV) candidate vaccine in pigs, developed at RIBSP Republic of Kazakhstan and delivered with an adjuvant Montanide™ Gel 01 ST (D/KV/ADJ) was compared with a commercial killed PRRSV vaccine (NVDC-JXA1, C/KV/ADJ) used widely in swine herds of the Republic of Kazakhstan. Clinical parameters (body temperature and respiratory disease scores), virological and immunological profiles [ELISA and virus neutralizing (VN) antibody titers], macroscopic lung lesions and viral load in the lungs (quantitative real-time PCR and cell culture assay) were assessed in vaccinated and both genotype 1 and 2 PRRSV challenged pigs. The challenge virus strains LKZ/2010 and CM/08 were propagated in MARC-145 cells, and confirmed as type 1 and type 2 viruses by EZ-PRRSV TM MPX 4.0 Real Time RT-PCR using Target-Specific Reagents kit for the Rapid Identification & Differentiation of North American and European PRRS Viral RNA (Tetracore, MD, USA).

title:
  Inactivated porcine reproductive and respiratory syndrome virus vaccine adjuvanted with Montanide™ Gel 01 ST elicits virus-specific cross-protective inter-genotypic response in piglets

abstract:
  The efficacy of a novel BEI-inactivated porcine reproductive and respiratory syndrome virus (PRRSV) candidate vaccine in pigs, developed at RIBSP Republic of Kazakhstan and delivered with an adjuvant Montanide™ Gel 01 ST (D/KV/ADJ) was compared with a commercial killed PRRSV vaccine (NVDC-JXA1, C/KV/ADJ) used widely in swine herds of the Republic of Kazakhstan. Clinical parameters (body temperature and respiratory disease scores), virological and immunological profiles [ELISA and virus neutralizing (VN) antibody titers], macroscopic lung lesions and viral load in the lungs (quantitative real-time PCR and cell culture assay) were assessed in vaccinated and both genotype 1 and 2 PRRSV challenged pigs. Our results showed that the commercial vaccine failed to protect pigs adequately against the clinical disease, viremia and lung lesions caused by the challenged field isolates, Kazakh strains of PRRSV type 1 and type 2 genotypes. In contrast, clinical protection, absence of viremia and lung lesions in D/KV/ADJ vaccinated pigs was associated with generation of VN antibodies in both homologous vaccine strain LKZ/2010 (PRRSV type 2) and a heterogeneous type 1 PRRSV strain (CM/08) challenged pigs. Thus, our data indicated the induction of cross-protective VN antibodies by D/KV/ADJ vaccine, and importantly demonstrated that an inactivated PRRSV vaccine could also induce cross-protective response across the viral genotype.


id: cord-301563-s0ypy2hf
author: Wang, Dang
date: 2015-09-03
txt: ./txt/cord-301563-s0ypy2hf.txt
cache: ./cache/cord-301563-s0ypy2hf.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0161589015300602
doi: 10.1016/j.molimm.2015.08.011
summary:
  For example, human immunodeficiency virus 1 (HIV-1) prevents antiviral interferon response via Vpr-and Vif-directed, ubiquitin-mediated proteosomal degradation of interferon regulatory factor 3 (IRF-3) (Okumura et al., 2008) ; the papain-like protease (PLpro) domains of many coronaviruses, such as severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), human coronavirus NL63 (HCoV-NL63), and mouse hepatitis virus A59 (MHV-A59), have deubiquitinating (DUB) activity that blocks type I interferons (IFNs) induction (Barretto et al., 2005; Chen et al., 2007b; Clementz et al., 2010; Devaraj et al., 2007; Frieman et al., 2009; Lindner et al., 2005; Zheng et al., 2008) ; the leader proteinase (L pro ) of Foot-and-mouth virus (FMDV) acts as a deubiquitinase that cleaves ubiquitin chains from retinoic acid-inducible gene I (RIG-I), TANK-binding kinase 1 (TBK1), TNF receptor associated factor 6 (TRAF6), and TRAF3, thereby inhibiting the activation of type I IFN signaling ; the N-terminal protease (Npro) of bovine viral diarrhea virus interacts with IRF-3 and promotes its polyubiquitination and subsequent degradation through the proteasome (Chen et al., 2007a) ; the latency associated protein ORF73 of murid herpesvirus-4 (MuHV-4) associates with the host ubiquitin-ligase complex to promote poly-ubiquitination and subsequent proteasomal degradation of p65/RelA, which inhibits the activity of nuclear factor B (NF-B) to facilitate the establishment of MuHV-4 latency (Rodrigues et al., 2009) .

title:
  The nonstructural protein 11 of porcine reproductive and respiratory syndrome virus inhibits NF-κB signaling by means of its deubiquitinating activity

abstract:
  Since its emergence in the late 1980s, porcine reproductive and respiratory syndrome (PRRS) has been devastating the swine industry worldwide. The causative agent is an Arterivirus, referred to as PRRS virus (PRRSV). The pathogenic mechanisms of PRRS are poorly understood, but are believed to correlate with the ability of PRRSV to inhibit immune responses of the host. However, precisely how the virus is capable of doing so remains obscure. In this study, we showed that PRRSV infection led to reduced ubiquitination of cellular proteins. Screening all of the 12 nonstructural proteins (Nsps) encoded by PRRSV revealed that, apart from the Nsp2 which contains the deubiqintinating (DUB) ovarian tumor (OTU) domain, Nsp11, which encodes a unique and conserved endoribonuclease (NendoU) throughout the Nidovirus order, also possesses DUB activity. In vivo assay demonstrated that Nsp11 specifically removed lysine 48 (K48)-linked polyubiquitin chains and the conserved sites C112, H144, D173, K180, and Y219 were critical for its DUB activity. Remarkably, DUB activity was responsible for the capacity of Nsp11 to inhibit nuclear factor κB (NF-κB) activation. Mutations abrogating the DUB activity of Nsp11 toward K48-linked polyubiquitin chains of IκBα nullified the suppressive effect on NF-κB. Our data add Nsp11 to the list of DUBs encoded by PRRSV and uncover a novel mechanism by which PRRSV cripples host innate immune responses.


id: cord-301692-zu0ubwfq
title: The challenge of PRRS immunology
author: Mateu, E.
date: 2007-07-20
url: https://www.ncbi.nlm.nih.gov/pubmed/17644436/
doi: 10.1016/j.tvjl.2007.05.022
abstract:
  Porcine reproductive and respiratory syndrome (PRRS) is one of the most challenging subjects of research in veterinary viral immunology, and the immune response against PRRS virus (PRRSV) still is poorly understood. Infected pigs develop a strong and rapid humoral response but these initial antibodies do not confer protection and can even be harmful by mediating an antibody-dependent enhancement of disease. In contrast, development of neutralising antibodies (NAs) is delayed and generation of cell-mediated immune responses, such as PRRSV-specific interferon (IFN)-γ secreting cells, is initially erratic. In spite of this, induction of strong and rapid NAs and IFN-γ responses seem to be required for effective vaccination. PRRSV strongly modulates the host’s immune responses. The virus inhibits key cytokines, such as IFN-α, and may induce regulatory cytokines, such as interleukin (IL)-10. Development of NAs seems to be impaired by the existence of a decoy epitope close to the main neutralisation epitope in glycoprotein 5. This ability to modulate the host immune response probably varies among strains or isolates. The genetic diversity of the virus is very high and it has been shown that this diversity can have serious implications for the development of vaccines, since the immunity induced by one strain may be only partial against a different strain, even within the same genotype. With this panorama, the development of newer and universally efficacious PRRSV vaccines is challenging, but the present state of knowledge allows optimism if collaborative efforts are undertaken in the scientific community.


id: cord-302306-fudeixy2
author: Xu, Kui
date: 2020-09-02
txt: ./txt/cord-302306-fudeixy2.txt
cache: ./cache/cord-302306-fudeixy2.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.7554/elife.57132
doi: 10.7554/elife.57132
summary:
  Here, we report generation of double-gene-knockout (DKO) pigs harboring edited knockout alleles for known receptor proteins CD163 and pAPN and show that DKO pigs are completely resistant to genotype 2 PRRSV and TGEV. Additional infection challenge experiments showed that DKO pigs exhibited decreased susceptibility to porcine deltacoronavirus (PDCoV), thus offering unprecedented in vivo evidence of pAPN as one of PDCoV receptors. Through viral challenge experiments, we found that these DKO pigs exhibit complete resistance to genotype 2 PRRSV and TGEV, and exhibit decreased susceptibility to PDCoV infection. Thus, in addition to demonstrating that our DKO pigs are robustly resistant to both PRRSV and TGEV without suffering deleterious effects for production performance, our study also provides insights into ongoing controversy about the pAPN protein as a potential receptor for PDCoV infection of pigs. pAPN protospacer PAM In order to generate more DKO pigs for viral challenge experiments, we collected ear tissue samples from three piglets (#1143, #1144, and #1145) and isolated ear-derived fibroblasts.

title:
  CD163 and pAPN double-knockout pigs are resistant to PRRSV and TGEV and exhibit decreased susceptibility to PDCoV while maintaining normal production performance

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) and transmissible gastroenteritis virus (TGEV) are two highly infectious and lethal viruses causing major economic losses to pig production. Here, we report generation of double-gene-knockout (DKO) pigs harboring edited knockout alleles for known receptor proteins CD163 and pAPN and show that DKO pigs are completely resistant to genotype 2 PRRSV and TGEV. We found no differences in meat-production or reproductive-performance traits between wild-type and DKO pigs, but detected increased iron in DKO muscle. Additional infection challenge experiments showed that DKO pigs exhibited decreased susceptibility to porcine deltacoronavirus (PDCoV), thus offering unprecedented in vivo evidence of pAPN as one of PDCoV receptors. Beyond showing that multiple gene edits can be combined in a livestock animal to achieve simultaneous resistance to two major viruses, our study introduces a valuable model for investigating infection mechanisms of porcine pathogenic viruses that exploit pAPN or CD163 for entry.


id: cord-306948-wkisfz1m
title: Engineering the PRRS virus genome: Updates and perspectives
author: Han, Mingyuan
date: 2014-12-05
url: https://doi.org/10.1016/j.vetmic.2014.10.007
doi: 10.1016/j.vetmic.2014.10.007
abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) is endemic in most pig producing countries worldwide and causes enormous economic losses to the pork industry. Infectious clones for PRRSV have been constructed, and so far at least 14 different infectious clones are available representing both genotypes I and II. Two strategies have been taken for progeny reconstitution: RNA transfection and DNA transfection. Mutations, insertions, deletions, and replacements of the viral genome have been employed to study the structure function relationship, foreign gene expression, functional complementation, and virulence determinants. Essential regions and non-essential regions for viral replication have been identified in both the coding regions and non-encoding regions. Foreign sequences have successfully been inserted into the nsp2 and N regions and in the space between ORF1b and ORF2a. Chimeras between member viruses in the family Arteriviridae have also been constructed and utilized to study cell tropism and functional complementation. This review discusses the advances and utilization of PRRSV reverse genetics and its potential for future research.


id: cord-307073-vatfdilt
author: Narita, M.
date: 2004-08-11
url: https://api.elsevier.com/content/article/pii/S0021997504000660
doi: 10.1016/j.jcpa.2004.05.001
title:
  Encephalomalacic Lesions in Pigs Dually Infected with Porcine Reproductive and Respiratory Syndrome Virus and Pseudorabies Virus

abstract:
  Four pigs (group 1) were infected with an aerosol containing porcine reproductive and respiratory syndrome virus (PRRSV) followed 7 days later by pseudorabies virus (PRV). Three further pigs (group 2) received PRRSV alone, two (group 3) received PRV alone, and two (group 4) remained as uninfected controls. Despite the admittedly small numbers of animals, the experiment appeared to throw light on aspects of synergy. Thus, the group 1 pigs showed severe neurological signs characterized by ataxia and muscular tremors. Total cell numbers in the bronchoalveolar lavage fluid were increased in all PRRSV-infected pigs, and PRRSV antigen was detected in the alveolar macrophages. Total cell numbers in the cerebrospinal fluid of group 1 pigs were considerably greater than those demonstrated in group 3, but no PRV antigen was found. Pigs of groups 1 and 2 showed pulmonary lesions, characterized by interstitial pneumonia and PRRSV antigen immunolabelling. Non-suppurative encephalitis was found in five of the six pigs of groups 1 and 3. In particular, one group 1 animal had severe necrotizing encephalitis with intranuclear inclusion bodies and associated immunolabelling of PRV antigen. The other three group 1 pigs had prominent malacic lesions, with macrophages. These neuropathological findings strongly suggested that PRRSV infection in pigs enhances the severity of brain lesions caused PRV.


id: cord-309428-qkjjxr6p
author: Li, Liwei
date: 2015-01-02
txt: ./txt/cord-309428-qkjjxr6p.txt
cache: ./cache/cord-309428-qkjjxr6p.txt
extension: .txt
mime: text/plain
url: https://www.sciencedirect.com/science/article/pii/S0168170214003402
doi: 10.1016/j.virusres.2014.08.012
summary:
  MicroRNAs (miRNAs) play important roles in viral infections, especially by modulating the expression of cellular factors essential to viral replication or the host innate immune response to infection. To identify host miRNAs important to controlling porcine reproductive and respiratory syndrome virus (PRRSV) infection, we screened 15 miRNAs that were previously implicated in innate immunity or antiviral functions. Luciferase reporters showed that miR-26a does not target the PRRSV genome directly but instead affects the expression of type I interferon and the IFN-stimulated genes MX1 and ISG15 during PRRSV infection. We found that miR-26a does not target the PRRSV genome directly, but rather affects the expression of type I interferon and the IFN-stimulated genes MX1 and ISG15 during PRRSV infection. Indirect immunofluorescence assays (IFA) were performed as described previously (Tian et al., 2011) for the detection of nucleocapsid (N) protein in PRRSV vJX143 infected MARC-145 cells or PAMs pre-transfected with miR-26 family or mutant mimics.

title:
  Host miR-26a suppresses replication of porcine reproductive and respiratory syndrome virus by upregulating type I interferons

abstract:
  MicroRNAs (miRNAs) play important roles in viral infections, especially by modulating the expression of cellular factors essential to viral replication or the host innate immune response to infection. To identify host miRNAs important to controlling porcine reproductive and respiratory syndrome virus (PRRSV) infection, we screened 15 miRNAs that were previously implicated in innate immunity or antiviral functions. Over-expression of the miR-26 family strongly inhibited PRRSV replication in vitro, as shown by virus titer assays, Western blotting, and qRT-PCR assays. MiR-26a inhibited the replication of both type 1 and type 2 PRRSV strains. Mutating the seed region of miR-26 restored viral titers. Luciferase reporters showed that miR-26a does not target the PRRSV genome directly but instead affects the expression of type I interferon and the IFN-stimulated genes MX1 and ISG15 during PRRSV infection. These results demonstrate the important role of miR-26a in modulating PRRSV infection and also support the possibility of using host miR-26a to achieve RNAi-mediated antiviral therapeutic strategies.


id: cord-310771-tnwfp1je
author: Revilla-Fernández, Sandra
date: 2005-02-23
txt: ./txt/cord-310771-tnwfp1je.txt
cache: ./cache/cord-310771-tnwfp1je.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/15847915/
doi: 10.1016/j.jviromet.2005.01.018
summary:
  A method was developed for qualitative and quantitative detection of the seminal cell-associated PRRSV RNA in relation to endogenous and exogenous reference RNAs. As endogenous control for one-step real-time reverse transcription (RT)-PCR UBE2D2 mRNA was selected. Particularly for the analysis of persistent infections associated with low copy numbers of PRRSV RNA, UBE2D2 mRNA is an ideal control due to its low expression in seminal cells and its detection in all samples analysed (n = 36). For the development of one-step real-time RT-PCR for four endogenous reference RNAs (HPRT, UBE2D2, PPIA, and HMBS) appropriate target regions were selected and the assay conditions were optimised for amplification efficiency. One-step real-time RT-PCR assays for PRRSV-1 and -2 RNA allowed quantitation with optimal efficiency (Fig. 1a ; standard curves for two additional viremic pigs infected with PRRSV-1 (data not shown)) as achieved for endogenous and Fig. 1 .

title:
  The use of endogenous and exogenous reference RNAs for qualitative and quantitative detection of PRRSV in porcine semen

abstract:
  Semen is known to be a route of porcine reproductive and respiratory syndrome virus (PRRSV) transmission. A method was developed for qualitative and quantitative detection of the seminal cell-associated PRRSV RNA in relation to endogenous and exogenous reference RNAs. As endogenous control for one-step real-time reverse transcription (RT)-PCR UBE2D2 mRNA was selected. Particularly for the analysis of persistent infections associated with low copy numbers of PRRSV RNA, UBE2D2 mRNA is an ideal control due to its low expression in seminal cells and its detection in all samples analysed (n = 36). However, the amount of UBE2D2 mRNA in porcine semen varied (up to 106-fold), thus its use is limited to qualitative detection of PRRSV RNA. For quantitation, a synthetic, non-metazoan RNA was added to the RNA isolation reaction at an exact copy number. The photosynthesis gene ribulose-1,5-bisphosphate carboxylase/oxygenase large subunit (rbcL) from Arabidopsis thaliana was used as an exogenous spike. Unexpectedly, PRRSV RNA was detected in a herd of specific pathogen-free (SPF) boars which were tested ELISA-negative for anti-PRRSV antibodies. Therefore, RT-PCR for seminal cell-associated PRRSV is a powerful tool for managing the SPF status during quarantine programs and for routine outbreak investigations.


id: cord-312208-8ydh6jev
author: Meng, X.J
date: 2000-06-12
url: https://www.ncbi.nlm.nih.gov/pubmed/10831854/
doi: 10.1016/s0378-1135(00)00196-6
title:
  Heterogeneity of porcine reproductive and respiratory syndrome virus: implications for current vaccine efficacy and future vaccine development

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) continues to be a major problem to the pork industry worldwide. Increasing data indicate that PRRSV strains differ in virulence in infected pigs and are biologically, antigenically, and genetically heterogeneous. It is evident that the current vaccines, based on a single PRRSV strain, are not effective in protecting against infections with the genetically diverse field strains of PRRSV. The recent outbreaks of atypical or acute PRRS in vaccinated pigs have raised a serious concern about the efficacy of the current vaccines and provided the impetus for developing more effective vaccines. Special attention in this review is given to published work on antigenic, pathogenic and genetic variations of PRRSV and its potential implications for vaccine efficacy and development. Although there are ample data documenting the heterogeneous nature of PRRSV strains, information regarding how the heterogeneity is generated and what clinical impact it may have is very scarce. The observed heterogeneity will likely pose a major obstacle for effective prevention and control of PRRS. There remains an urgent need for fundamental research on this virus to understand the basic biology and the mechanism of heterogeneity and pathogenesis of PRRSV.


id: cord-312787-j7ye7ed5
author: Loemba, H. D.
date: 1996
txt: ./txt/cord-312787-j7ye7ed5.txt
cache: ./cache/cord-312787-j7ye7ed5.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/8645111/
doi: 10.1007/bf01718333
summary:
  coli-expressed ORFs 5 to 7 gene products, suggested that antibodies directed against the envelope E protein appear by day 7 p.i., whereas antibodies directed against the nucleocapsid N and membrane M proteins can only be detected by the end of the second week p.i. No correlation could be demonstrated between VN and IIF antibody titers, viremia, and viral protein specificities of circulating antibodies at various times p.i. Summary. coli-expressed ORFs 5 to 7 gene products, suggested that antibodies directed against the envelope E protein appear by day 7 p.i., whereas antibodies directed against the nucleocapsid N and membrane M proteins can only be detected by the end of the second week p.i. No correlation could be demonstrated between VN and IIF antibody titers, viremia, and viral protein specificities of circulating antibodies at various times p.i. The porcine reproductive and respiratory syndrome virus (PRRSV) is an enveloped RNA virus which has been found to be responsible for reproductive failure in sows of any parities (late-term abortions, increased numbers of stillborn, mummified and weakborn pigs) and respiratory problems affecting pigs of all ages [8, 20] .

title:
  Kinetics of humoral immune response to the major structural proteins of the porcine reproductive and respiratory syndrome virus

abstract:
  The kinetics of appearance of antibodies directed to the major structural proteins N, M and E of porcine reproductive and respiratory syndrome virus (PRRSV) was followed in pigs naturally- and experimentally-exposed to the virus. Specific IgM antibody titers were first detected by indirect immunofluorescence (IIF) at the end of the first week of PRRSV infection, peaked by day 14 to 21 post-inoculation (p.i.), then rapidly decreased to undetectable levels by day 35 to 42 p.i. On the other hand, specific IgG antibody titers peaked by day 21 to 28 p.i. and remained unchanged to the end of the 6- or 9-week observation period; in addition, a persistent viremia was observed. Virus neutralizing (VN) antibody titers >8 were not detected until 3 to 4 weeks p.i. Taken together, the results obtained by Western blotting analyses using purified virus andE. coli-expressed ORFs 5 to 7 gene products, suggested that antibodies directed against the envelope E protein appear by day 7 p.i., whereas antibodies directed against the nucleocapsid N and membrane M proteins can only be detected by the end of the second week p.i. No correlation could be demonstrated between VN and IIF antibody titers, viremia, and viral protein specificities of circulating antibodies at various times p.i.


id: cord-313445-4v7pjqt2
author: Zhao, Jun
date: 2020-10-28
txt: ./txt/cord-313445-4v7pjqt2.txt
cache: ./cache/cord-313445-4v7pjqt2.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/33115475/
doi: 10.1186/s12917-020-02627-6
summary:
  title: Porcine interferon lambda 3 (IFN-λ3) shows potent anti-PRRSV activity in primary porcine alveolar macrophages (PAMs) In addition, IFN-λ3 in our study was able to induce the expression of interferon-stimulated genes 15 (ISG15), 2′-5′-oligoadenylate synthase 1 (OAS1), IFN-inducible transmembrane 3 (IFITM3), and myxoma resistance protein 1(Mx1) in primary PAMs. CONCLUSIONS: IFN-λ3 had antiviral activity against PRRSV and can stimulate the expression of pivotal interferon-stimulated genes (ISGs), i.e., ISG15, Mx1, OAS1, and IFITM3. The virus titre was significantly reduced with the increase of IFN-λ3 treatment dose (10, Fig. 1 The CPE of primary PAMs treated with Porcine IFN-λ3 and infected with PRRSV. The expression of mRNA for ISG15, Mx1, OAS1, and IFIT M3 was up-regulated by 70, 70, 160, and 15 times respectively at the concentration of 1000 ng/ml in primary PAMs. As shown in Fig. 3e and f (The full-length blots are presented in Supplementary file 2), a dosedependent induction of the antiviral proteins ISG15, Mx1 and OAS1 has been observed in primary PAMs treated with IFN-λ3.

title:
  Porcine interferon lambda 3 (IFN-λ3) shows potent anti-PRRSV activity in primary porcine alveolar macrophages (PAMs)

abstract:
  BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is a serious viral disease of swine. At present, there are vaccines for the control of PRRSV infection, but the effect is not satisfactory. The recombination of attenuated vaccines causes significant difficulties with the prevention and control of PRRSV. Type III interferons (IFNs), also called IFN-λs, were newly identified and showed potent antiviral activity within the mucosal surface and immune organs. RESULTS: Therefore, primary porcine alveolar macrophages (PAMs) were used for this investigation. To this end, we found that the replication of PRRSV in PAMs was significantly reduced after pre-treatment with IFN-λ3, and such inhibition was dose- and time-dependent. The plaque formation of PRRSV abrogated entirely, and virus yields were reduced by four orders of magnitude when the primary PAMs were treated with IFN-λ3 at 1000 ng/ml. In addition, IFN-λ3 in our study was able to induce the expression of interferon-stimulated genes 15 (ISG15), 2′-5′-oligoadenylate synthase 1 (OAS1), IFN-inducible transmembrane 3 (IFITM3), and myxoma resistance protein 1(Mx1) in primary PAMs. CONCLUSIONS: IFN-λ3 had antiviral activity against PRRSV and can stimulate the expression of pivotal interferon-stimulated genes (ISGs), i.e., ISG15, Mx1, OAS1, and IFITM3. So, IFN-λ3 may serve as a useful antiviral agent. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-020-02627-6.


id: cord-319779-n5w1f0rr
author: Lee, Sang-Myeong
date: 2004-12-08
txt: ./txt/cord-319779-n5w1f0rr.txt
cache: ./cache/cord-319779-n5w1f0rr.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0165242704002557
doi: 10.1016/j.vetimm.2004.09.009
summary:
  North American porcine reproductive and respiratory syndrome virus (PRRSV) field isolates were studied with regard to IFN-α sensitivity and induction in order to understand the role of type I IFN in PRRSV pathogenesis. PRRSV isolates were differentially sensitive to porcine recombinant IFN-α (rIFN-α) and varied in their ability to induce IFN-α in porcine alveolar macrophages (PAM) cultures as measured by a porcine IFN-α specific ELISA on cell culture supernatants. In this study, North American field isolates of PRRSV were evaluated with respect to induction, sensitivity and suppression of an in vitro type I IFN response. UV-inactivated PRRSV stocks were tested to determine whether virus binding to the cells is responsible for enhanced IFN-a production by polyI:C in cells infected with isolate 3 (Fig. 6) . In this study, North American PRRSV field isolates were evaluated with respect to induction, sensitivity and suppression of an in vitro IFN response in PAM cultures. Immune responses in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV)

title:
  Porcine reproductive and respiratory syndrome virus field isolates differ in in vitro interferon phenotypes

abstract:
  Type I interferons (IFN-α and -β) play an important role in the innate host defense against viral infection by inducing antiviral responses. In addition to direct antiviral activities, type I IFN serves as an important link between the innate and adaptive immune response through multiple mechanisms. Therefore, the outcome of a viral infection can be affected by IFN induction and the IFN sensitivity of a virus. North American porcine reproductive and respiratory syndrome virus (PRRSV) field isolates were studied with regard to IFN-α sensitivity and induction in order to understand the role of type I IFN in PRRSV pathogenesis. PRRSV isolates were differentially sensitive to porcine recombinant IFN-α (rIFN-α) and varied in their ability to induce IFN-α in porcine alveolar macrophages (PAM) cultures as measured by a porcine IFN-α specific ELISA on cell culture supernatants. Fifty-two plaques were purified from three PRRSV isolates (numbers 3, 7, and 12) and tested for IFN sensitivity and IFN induction. Plaque-derived populations were composed of heterogeneous populations in terms of IFN-inducing capacity and sensitivity to rIFN-α. When macrophages infected with isolates 3, 7, or 12 were treated with polycytidylic acid (polyI:C), IFN-α production was enhanced. Cells infected with isolate 3 and treated with polyI:C showed the most consistent and strongest enhancement of IFN-α production. It was demonstrated that the relatively low concentrations of IFN-α produced by isolate 3 contributed to the enhanced IFN-α synthesis in response to polyI:C. Isolates 7 and 12 significantly suppressed the enhanced IFN-α production by isolate 3 in polyI:C treated cells. To determine if suppression was at the level of IFN-α transcription, quantitative RT-PCR was performed for IFN-α mRNA and compared to GAPDH and cyclophilin mRNA quantification. However, the relative number of IFN-α transcript copies did not correlate with IFN-α protein levels, suggesting a post-transcriptional mechanism of suppression. In summary, these results demonstrate that PRRSV field isolates differ both in IFN-α sensitivity and induction. Furthermore, a PRRSV field isolate strongly enhance polyI:C-induced IFN-α production in PAM cultures and this priming effect was suppressed by other PRRSV isolates.


id: cord-321195-cndq6aqb
author: Xue, Chunyi
date: 2014-07-27
url: https://doi.org/10.1007/s00705-014-2178-0
doi: 10.1007/s00705-014-2178-0
title:
  Chimeric influenza-virus-like particles containing the porcine reproductive and respiratory syndrome virus GP5 protein and the influenza virus HA and M1 proteins

abstract:
  Both porcine reproductive and respiratory syndrome and swine influenza are acute, highly contagious swine diseases. These diseases pose severe threats for the swine industry and cause heavy economic losses worldwide. In this study, we have developed a chimeric virus-like particle (VLP) vaccine candidate for porcine reproductive and respiratory syndrome virus (PRRSV) and H3N2 influenza virus and investigated its immunogenicity in mice. The HA and M1 proteins from the H3N2 influenza virus and the PRRSV GP5 protein fused to the cytoplasmic and transmembrane domains of the NA protein were both incorporated into the chimeric VLPs. Analysis of the immune responses showed that the chimeric VLPs elicited serum antibodies specific for both PRRSV GP5 and the H3N2 HA protein, and they stimulated cellular immune responses compared to the responses to equivalent amounts of inactivated viruses. Taken together, the results suggested that the chimeric VLP vaccine represents a potential strategy for the development of a safe and effective vaccine to control PRRSV and H3N2 influenza virus.


id: cord-321471-gev5xq3a
title: Control of the PI3K/Akt pathway by porcine reproductive and respiratory syndrome virus
author: Zhu, Liqian
date: 2013-02-05
url: https://www.ncbi.nlm.nih.gov/pubmed/23381397/
doi: 10.1007/s00705-013-1620-z
abstract:
  Phosphatidylinositol-3-kinase (PI3K)/Akt is an important cellular pathway that has been shown to participate in various replication steps of multiple viruses. In the present study, we compared the phosphorylation status of Akt during infection of MARC-145 cells and porcine alveolar macrophages (PAMs) with highly pathogenic PRRSV (HP-PRRSV) strain HuN4. We observed that biphasic activation of Akt was induced in at both the early stage (5, 15 and 30 min postinfection) and the late stage (12 and 24 h postinfection) of HP-PRRSV infection of MARC-145 cells, while an early-phase activation of Akt was found exclusively in virus-infected PAMs in vitro. Analysis with the PI3K-specific inhibitor LY294002 confirmed that PI3K acted as the upstream activator for the virus-induced activation of Akt. UV-irradiation-inactivated virus still induced the early event in PAMs but not in MARC-145 cells, suggesting that different mechanisms are employed for the early-stage induction of phosphorylated Akt within different cell cultures. We further demonstrated that FoxO1 and Bad, which serve as downstream targets of Akt, were phosphorylated in virus-infected MARC-145 cells. Moreover, the suppression of phosphorylated Akt with LY294002 significantly inhibited the virus-induced cytopathic effect (CPE) on MARC-145 cells, but it had a negligible effect on virus propagation. Collectively, our data provide new evidence of a novel role for the PI3K/Akt pathway in PRRSV infection of MARC-145 cells.


id: cord-322593-bgm6smuo
author: Li, Lan
date: 2016-04-21
url: https://doi.org/10.1007/s00705-016-2838-3
doi: 10.1007/s00705-016-2838-3
title:
  Antiviral activity of recombinant porcine surfactant protein A against porcine reproductive and respiratory syndrome virus in vitro

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) has caused significant economic losses in the swine industry worldwide. However, there is not an ideal vaccine to provide complete protection against PRRSV. Thus, the need for new antiviral strategies to control PRRSV still remains. Surfactant protein A (SP-A) belongs to the family of C-type lectins, which can exert antiviral activities. In this present study, we assessed the antiviral properties of recombinant porcine SP-A (RpSP-A) on PRRSV infection in Marc 145 cells and revealed its antiviral mechanism using a plaque assay, real-time qPCR, western blotting analysis and an attachment and penetration assay. Our results showed that RpSP-A could inhibit the infectivity of PRRSV in Marc 145 cells and could reduce the total RNA and protein level. The attachment assay indicated that RpSP-A in the presence of Ca(2+) could largely inhibit Marc 145 cell attachment; however, in the penetration assay, it was relatively inactive. Furthermore, our study suggested that virus progeny released from infected Marc145 cells were blocked by RpSP-A from infecting other cells. We conclude that RpSP-A has antiviral activity against PRRSV, most probably by blocking viral attachment and the cell-to-cell transmission pathway, and therefore, RpSP-A holds promise as a novel antiviral agent against PRRSV.


id: cord-324495-0pee1i3o
author: Kang, Hyeonjeong
date: 2015-06-06
url: https://www.ncbi.nlm.nih.gov/pubmed/26047649/
doi: 10.1007/s00705-015-2469-0
title:
  Sasa quelpaertensis Nakai extract suppresses porcine reproductive and respiratory syndrome virus replication and modulates virus-induced cytokine production

abstract:
  Although Sasa quelpaertensis Nakai, a dwarf bamboo, is known to exert a variety of beneficial effects on health, its antiviral effect remains to be elucidated. Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most devastating viral pathogens of swine and has a substantial economic impact on the global pork industry. Therefore, the present study was conducted to determine whether Sasa quelpaertensis Nakai extract (SQE) inhibits PRRSV infection in cultured porcine alveolar macrophages (PAMs). Our results demonstrated that SQE treatment suppressed the replication of PRRSV in a dose-dependent manner. The antiviral activity of SQE on PRRSV replication was found to be primarily exerted at early times postinfection. Treatment with SQE resulted in marked reduction of viral genomic and subgenomic RNA synthesis, viral protein expression, and progeny virus production. Notably, pro-inflammatory cytokine production in PAM cells infected with PRRSV was shown to be modulated in the presence of SQE. Taken together, our data indicate that SQE has potential as a therapeutic agent against PRRSV. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00705-015-2469-0) contains supplementary material, which is available to authorized users.


id: cord-324950-ux7shvji
title: Coinfections and their molecular consequences in the porcine respiratory tract
author: Saade, Georges
date: 2020-06-16
txt: ./txt/cord-324950-ux7shvji.txt
cache: ./cache/cord-324950-ux7shvji.txt
extension: .txt
mime: text/plain
url: https://doi.org/10.1186/s13567-020-00807-8
doi: 10.1186/s13567-020-00807-8
summary:
  In pigs, the term "Porcine Respiratory Disease Complex" (PRDC) is often used to describe coinfections involving viruses such as swine Influenza A Virus (swIAV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Porcine CircoVirus type 2 (PCV2) as well as bacteria like Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae and Bordetella bronchiseptica. The outcome of any coinfection or superinfection can be affected by the interactions taking place between the infectious agents, the nature of the cell/host, adverse environmental and management conditions, intestinal and respiratory microbiomes, and the triggered immune response-innate and adaptive-developed afterwards [2, 3] . It is well-known that viral infections can induce an ideal environment for a bacterial superinfection through different mechanisms such as the destruction of the epithelial barrier, the over-expression of the receptors involved in the bacterial adhesion to the cells, and the alteration of the host immune response [1, 2, 94, 95] .

abstract:
  Understudied, coinfections are more frequent in pig farms than single infections. In pigs, the term “Porcine Respiratory Disease Complex” (PRDC) is often used to describe coinfections involving viruses such as swine Influenza A Virus (swIAV), Porcine Reproductive and Respiratory Syndrome Virus (PRRSV), and Porcine CircoVirus type 2 (PCV2) as well as bacteria like Actinobacillus pleuropneumoniae, Mycoplasma hyopneumoniae and Bordetella bronchiseptica. The clinical outcome of the various coinfection or superinfection situations is usually assessed in the studies while in most of cases there is no clear elucidation of the fine mechanisms shaping the complex interactions occurring between microorganisms. In this comprehensive review, we aimed at identifying the studies dealing with coinfections or superinfections in the pig respiratory tract and at presenting the interactions between pathogens and, when possible, the mechanisms controlling them. Coinfections and superinfections involving viruses and bacteria were considered while research articles including protozoan and fungi were excluded. We discuss the main limitations complicating the interpretation of coinfection/superinfection studies, and the high potential perspectives in this fascinating research field, which is expecting to gain more and more interest in the next years for the obvious benefit of animal health.


id: cord-325875-93krp81r
title: Guidelines for oral fluid-based surveillance of viral pathogens in swine
author: Henao-Diaz, Alexandra
date: 2020-10-19
txt: ./txt/cord-325875-93krp81r.txt
cache: ./cache/cord-325875-93krp81r.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/33082999/
doi: 10.1186/s40813-020-00168-w
summary:
  (2020) showed that the probability of detecting porcine reproductive and respiratory syndrome virus (PRRSV) ribonucleic acid (RNA) in serum by reverse transcription polymerase chain reaction (RT-PCR) at 98 days post infection (DPI) was~2% versus~30% in lymphoid tissues (tonsil) by bioassay [16] . Similarly, differences in detection rates have been reported for pen-based oral fluids versus individual Table 1 provides examples of the detection of virus-specific nucleic acids and/or antibody in swine oral fluids, i.e., is not comprehensive b Acronyms defined in the list of abbreviations and terms pig buccal or nasal swabs for animals inoculated with FMDV, IAV, Senecavirus A (SVA), and swine vesicular disease virus (SVDV) [45, 62, 63, 68] . Diagnosis of the Lelystad strain of porcine reproductive and respiratory syndrome virus infection in individually housed pigs: comparison between serum and oral fluid samples for viral nucleic acid and antibody detection

abstract:
  Recent decades have seen both rapid growth and extensive consolidation in swine production. As a collateral effect, these changes have exacerbated the circulation of viruses and challenged our ability to prevent, control, and/or eliminate impactful swine diseases. Recent pandemic events in human and animal health, e.g., SARS-CoV-2 and African swine fever virus, highlight the fact that clinical observations are too slow and inaccurate to form the basis for effective health management decisions: systematic processes that provide timely, reliable data are required. Oral fluid-based surveillance reflects the adaptation of conventional testing methods to an alternative diagnostic specimen. The routine use of oral fluids in commercial farms for PRRSV and PCV2 surveillance was first proposed in 2008 as an efficient and practical improvement on individual pig sampling. Subsequent research expanded on this initial report to include the detection of ≥23 swine viral pathogens and the implementation of oral fluid-based surveillance in large swine populations (> 12,000 pigs). Herein we compile the current information regarding oral fluid collection methods, testing, and surveillance applications in swine production.


id: cord-328935-mn8r972x
title: Mucosal Veterinary Vaccines: Comparative Vaccinology
author: Hodgins, Douglas C.
date: 2015-03-13
txt: ./txt/cord-328935-mn8r972x.txt
cache: ./cache/cord-328935-mn8r972x.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/B9780124158474000689
doi: 10.1016/b978-0-12-415847-4.00068-9
summary:
  Studies of the potential of novel adjuvants to improve vaccine efficacy against genetically unstable, immune-subverting RNA viruses, such as porcine reproductive and respiratory syndrome virus in pigs, should assist in the control of pathogens with similar characteristics in other species. However, a recent study showed that an inactivated reassortant RV strain (CDC-9 strain) formulated with aluminum phosphate and administered systemically in gnotobiotic pigs resulted in induction of serum IgG antibody titers, coinciding with partial protection against shedding and diarrhea, suggesting that adjuvant may have stimulated local specific (gut IgA antibodies) or nonspecific immune responses, which were not assessed in this study (Wang et al., 2010) . Intranasal delivery of whole cell lysate of Mycobacterium tuberculosis induces protective immune responses to a modified live porcine reproductive and respiratory syndrome virus vaccine in pigs

abstract:
  Infections of mucosal surfaces are major causes of morbidity, mortality, and economic loss in species of veterinary interest, and a concern for animal welfare. Vaccines are used extensively in veterinary medicine, and innovative vaccine technologies such as recombinant DNA-vectored and distinguishing infected from vaccinated animals (DIVA) vaccines and automated in ovo vaccination (of embryonated chicken eggs) have been rapidly adopted commercially. Immunological research using outbred, nonrodent animal models has contributed to a broader understanding of mucosal defenses, and has provided the initial impetus for investigation of the common mucosal immune system. Studies of the potential of novel adjuvants to improve vaccine efficacy against genetically unstable, immune-subverting RNA viruses, such as porcine reproductive and respiratory syndrome virus in pigs, should assist in the control of pathogens with similar characteristics in other species. Successful development of vaccines to prevent and treat ascending infections of the reproductive tract of cattle set a precedent for applications in other species including humans. Studies of mucosal adjuvants and delivery systems continue at the interface between passive and active immunity, with the goal of inducing the earliest possible protection against enteric and respiratory pathogens of neonates.


id: cord-329274-ncvvmkca
author: Labarque, G
date: 2002-08-02
url: https://www.sciencedirect.com/science/article/pii/S0378113502001049
doi: 10.1016/s0378-1135(02)00104-9
title:
  Porcine reproductive–respiratory syndrome virus infection predisposes pigs for respiratory signs upon exposure to bacterial lipopolysaccharide

abstract:
  This study examined whether an infection with porcine reproductive and respiratory syndrome virus (PRRSV) potentiates respiratory signs upon exposure to bacterial lipopolysaccharides (LPS). Five-week-old conventional pigs were inoculated intratracheally with the Lelystad strain of PRRSV and received 5 days later one or two intratracheal LPS administrations. The necessary controls were included. After LPS administration, pigs were intensively monitored for clinical signs. Additionally, some pigs were euthanatized after a second LPS administration for broncho-alveolar cell analysis and virological examinations of the lungs. Broncho-alveolar lavage (BAL) cells were counted and differentiated. Lung suspensions and BAL fluids were titrated for PRRSV. Exposure of pigs to PRRSV only resulted in a fever for time periods ranging from 1 to 5 days and slight respiratory signs. Exposure of pigs to LPS only resulted in general signs, characterized by fever and depression, but respiratory signs were slight or absent. PRRSV–LPS exposed pigs, on the other hand, developed severe respiratory signs upon LPS exposure, characterized by tachypnoea, abdominal breathing and dyspnoea. Besides respiratory signs, these pigs also showed enhanced general signs, such as fever and depression. Lung neutrophil infiltration was similar in non-infected and PRRSV-infected pigs upon LPS exposure. PRRSV quantities were similar in lungs and BAL fluids of pigs infected with PRRSV only and PRRSV–LPS exposed pigs. These data show a clear synergism between PRRSV and LPS in the induction of respiratory signs in conventional pigs. The synergism was observed in 87% of the pigs. So, it can be considered as reproducible and may be used to test the efficacy of preventive and therapeutic measures.


id: cord-329625-hx2rsi91
author: You, Jae-Hwan
date: 2008-08-15
txt: ./txt/cord-329625-hx2rsi91.txt
cache: ./cache/cord-329625-hx2rsi91.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/18550142/
doi: 10.1016/j.virol.2008.04.037
summary:
  title: A model for the dynamic nuclear/nucleolar/cytoplasmic trafficking of the porcine reproductive and respiratory syndrome virus (PRRSV) nucleocapsid protein based on live cell imaging Porcine reproductive and respiratory syndrome virus (PRRSV), an arterivirus, in common with many other positive strand RNA viruses, encodes a nucleocapsid (N) protein which can localise not only to the cytoplasm but also to the nucleolus in virus-infected cells and cells over-expressing N protein. To investigate whether the trafficking of N protein between the cytoplasm and the nucleus/nucleolus was associated with microtubules or energy dependent, the mobility of EGFP-PRRSV-N protein was compared in 3D4/31 cells incubated at 37°C in the presence and absence of nocodazole (60ng/ml nocodazole (Sigma) for 16h), a microtubule inhibitor, or incubated at 10°C. In approximately 10% of cells expressing EGFP-PRRSV-N protein fluorescence was observed in the cytoplasm, but only if imaging was adjusted so that the fluorescent signal in the nucleus/nucleolus was above the linear range (for example Fig. 8C, lower panels) .

title:
  A model for the dynamic nuclear/nucleolar/cytoplasmic trafficking of the porcine reproductive and respiratory syndrome virus (PRRSV) nucleocapsid protein based on live cell imaging

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV), an arterivirus, in common with many other positive strand RNA viruses, encodes a nucleocapsid (N) protein which can localise not only to the cytoplasm but also to the nucleolus in virus-infected cells and cells over-expressing N protein. The dynamic trafficking of positive strand RNA virus nucleocapsid proteins and PRRSV N protein in particular between the cytoplasm and nucleolus is unknown. In this study live imaging of permissive and non-permissive cell lines, in conjunction with photo-bleaching (FRAP and FLIP), was used to investigate the trafficking of fluorescent labeled (EGFP) PRRSV-N protein. The data indicated that EGFP-PRRSV-N protein was not permanently sequestered to the nucleolus and had equivalent mobility to cellular nucleolar proteins. Further the nuclear import of N protein appeared to occur faster than nuclear export, which may account for the observed relative distribution of N protein between the cytoplasm and the nucleolus.


id: cord-330035-0d6w8xyd
title: Cellular cholesterol is required for porcine nidovirus infection
author: Jeon, Ji Hyun
date: 2017-09-07
url: https://doi.org/10.1007/s00705-017-3545-4
doi: 10.1007/s00705-017-3545-4
abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine epidemic diarrhea virus (PEDV) are porcine nidoviruses that are considered emerging and re-emerging viral pathogens of pigs that pose a significant economic threat to the global pork industry. Although cholesterol is known to affect the replication of a broad range of viruses in vitro, its significance and role in porcine nidovirus infection remains to be elucidated. Therefore, the present study was conducted to determine whether cellular or/and viral cholesterol levels play a role in porcine nidovirus infection. Our results showed that depletion of cellular cholesterol by treating cells with methyl-β-cyclodextrin (MβCD) dose-dependently suppressed the replication of both nidoviruses. Conversely, cholesterol depletion from the viral envelope had no inhibitory effect on porcine nidovirus production. The addition of exogenous cholesterol to MβCD-treated cells moderately restored the infectivity of porcine nidoviruses, indicating that the presence of cholesterol in the target cell membrane is critical for viral replication. The antiviral activity of MβCD on porcine nidovirus infection was found to be predominantly exerted when used as a treatment pre-infection or prior to the viral entry process. Furthermore, pharmacological sequestration of cellular cholesterol efficiently blocked both virus attachment and internalization and, accordingly, markedly affected subsequent post-entry steps of the replication cycle, including viral RNA and protein biosynthesis and progeny virus production. Taken together, our data indicate that cell membrane cholesterol is required for porcine nidovirus entry into cells, and pharmacological drugs that hamper cholesterol-dependent virus entry may have antiviral potential against porcine nidoviruses.


id: cord-332049-geh9aaf5
author: Wagner, Judith
date: 2010-01-20
txt: ./txt/cord-332049-geh9aaf5.txt
cache: ./cache/cord-332049-geh9aaf5.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S1090023309005115
doi: 10.1016/j.tvjl.2009.12.022
summary:
  Pulmonary dysfunction was evaluated in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV, isolate VR-2332) and compared to clinical and pathological findings. A combination of impulse oscillometry and rebreathing of test gases can be used to evaluate lung ventilation, respiratory mechanics and pulmonary gas exchange in spontaneously breathing pigs. Pulmonary function tests (PFTs) were performed twice before challenge (À7 and À3 days) and seven times after challenge (2, 4, 6, 9, 12, 15, 18 and 21 dpi) in eight pigs exposed to PRRSV and in eight controls (Table 1) . M. hyopneumoniae, Mycoplasma hyopneumoniae; APP, Actinobacillus pleuropneumoniae; PCV-2, porcine circovirus type 2; PRCV, porcine respiratory coronavirus; SIV, swine influenza virus; TGEV, transmissible gastroenteritis virus; PFT, pulmonary function tests (8 pigs per group examined postmortem at 21 dpi). Pulmonary function tests in PRRSV challenged pigs indicate both obstructive and restrictive disorders (confirmed by increased Rrs at frequencies 65 Hz and decreased Xrs), as well as disorders in gas exchange (confirmed by decreased TL CO Hb ).

title:
  Respiratory function and pulmonary lesions in pigs infected with porcine reproductive and respiratory syndrome virus

abstract:
  Pulmonary dysfunction was evaluated in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV, isolate VR-2332) and compared to clinical and pathological findings. Infected pigs developed fever, reduced appetite, respiratory distress and dullness at 9 days post-inoculation (dpi). Non-invasive pulmonary function tests using impulse oscillometry and rebreathing of test gases (He, CO) revealed peripheral airway obstruction, reduced lung compliance and reduced lung CO-transfer factor. PRRSV-induced pulmonary dysfunction was most marked at 9–18 dpi and was accompanied by a significantly increased respiratory rate and decreased tidal volume. Expiration was affected more than inspiration. On histopathological examination, multifocal areas of interstitial pneumonia (more severe and extensive at 10 dpi than 21 dpi) were identified as a possible structural basis for reduced lung compliance and gas exchange disturbances.


id: cord-332154-2gej7h1d
author: Meier, William A.
date: 2004-12-08
txt: ./txt/cord-332154-2gej7h1d.txt
cache: ./cache/cord-332154-2gej7h1d.txt
extension: .txt
mime: text/plain
url: https://api.elsevier.com/content/article/pii/S0165242704002636
doi: 10.1016/j.vetimm.2004.09.012
summary:
  Immunization of pigs with a modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine initially elicits a weak interferon (IFN)-γ response. Based on the success of this intervention and the noted absence of IFN-a generation during PRRSV infection, the present studies were undertaken to determine if the antiviral adaptive immunity induced by vaccination with PRRS MLV could be modified simply by the co-administration of rIL-12 protein directly, or of either porcine IFN-a or IL-12 indirectly via plasmids expressing these cytokines. Although a similar response was evident during this time period for vaccinated pigs also i.m. injected with exogenous IL-12 either directly as protein or indirectly via IL-12 cDNA, immunized animals that were i.d. inoculated with IL-12 cDNA exhibited an overall 2.7-fold transient increase in the frequency of PRRSV-specific IFN-g SC at 2 weeks post-vaccination. Immune responses in pigs infected with porcine reproductive and respiratory syndrome virus (PRRSV)

title:
  Cytokines and synthetic double-stranded RNA augment the T helper 1 immune response of swine to porcine reproductive and respiratory syndrome virus

abstract:
  Immunization of pigs with a modified live porcine reproductive and respiratory syndrome virus (PRRSV) vaccine initially elicits a weak interferon (IFN)-γ response. To improve the immune response, an adjuvant consisting of plasmid encoding either porcine interleukin (IL)-12 or IFN-α was co-administered during vaccination. In the presence of either adjuvant, at least a three-fold increase in the primary virus-specific IFN-γ response was observed. While this enhancement was only transient (1 week) when the IL-12 expressing plasmid was used, the effect was not only still apparent at 6 weeks after vaccination in the presence of the IFN-α expressing plasmid but even after challenge with a virulent genetically divergent PRRSV. In contrast, no effect of either adjuvant on the production of anti-virus antibodies was noticed throughout the study. Despite the apparent augmentation of a T helper (Th) 1 type response by the inclusion of IFN-α or IL-12 during vaccination, this modulation did not necessarily correlate with a reduction in viremia. Since a similar increase in the degree of the IFN-γ response to the PRRSV vaccine could be achieved by substituting polyinosinic–polycytidylic acid in lieu of either cytokine, exposure to PRRSV in the presence of a variety of Th 1 polarizing molecules can positively influence the development of the cell-mediated immune response of swine to this pathogen. Conceivably, such intervention could be applied to improve the formulation of anti-PRRSV vaccines.


id: cord-333349-tsfxpaj6
author: Chai, Weidong
date: 2014-08-08
url: https://www.ncbi.nlm.nih.gov/pubmed/25103309/
doi: 10.1186/1743-422x-11-140
title:
  Elevated dietary zinc oxide levels do not have a substantial effect on porcine reproductive and respiratory syndrome virus (PPRSV) vaccination and infection

abstract:
  BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important infectious agents for the swine industry worldwide. Zinc (Zn) salts, which are widely used as a dietary supplement in swine nutrition, have shown antiviral effects in vitro as well as in vivo. The purpose of this study was to determine the influence of dietary zinc oxide supplementation on vaccination and challenge infection with PRRSV. FINDINGS: The clinical course of PRRS and the success of vaccination with an experimental inactivated vaccine were compared between animals receiving a conventional diet (50 ppm Zn, control group) and diets supplemented with Zn oxide (ZnO) at final Zn concentrations of 150 or 2,500 ppm. Pigs receiving higher dietary Zn levels showed a tendency towards higher neutralizing antibody levels after infection, while dietary Zn levels did not substantially influence the number of antiviral IFN-gamma secreting cells (IFN-gamma-SC) or percentages of blood immune cell subsets after infection. Finally, feeding higher dietary Zn levels reduced neither clinical symptoms nor viral loads. CONCLUSIONS: Our results suggest that higher levels of dietary ZnO do not have the potential to stimulate or modulate systemic immune responses after vaccination and heterologous PRRSV infection to an extent that could improve the clinical and virological outcome. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1743-422X-11-140) contains supplementary material, which is available to authorized users.


id: cord-333423-jhm7u8ka
author: Wang, Dang
date: 2019-05-15
txt: ./txt/cord-333423-jhm7u8ka.txt
cache: ./cache/cord-333423-jhm7u8ka.txt
extension: .txt
mime: text/plain
url: https://jvi.asm.org/content/jvi/93/15/e00623-19.full.pdf
doi: 10.1128/jvi.00623-19
summary:
  Furthermore, the nsp11-IRF9 interaction impaired the formation and nuclear translocation of the transcription factor complex IFN-stimulated gene factor 3 (ISGF3) in both nsp11-overexpressed and PRRSV-infected cells. Taking the results together, our study demonstrated that PRRSV nsp11 antagonizes type I IFN signaling by targeting IRF9 via a NendoU activity-independent mechanism, and this report describes a novel strategy evolved by PRRSV to counteract host innate antiviral responses, revealing a potential new function for PRRSV nsp11 in type I IFN signaling. The type I IFN-activated ISGF3 transcription complex containing tyrosine-phosphorylated STAT1 and STAT2 associated with IRF9 is rapidly translocated to the nucleus FIG 3 PRRSV nsp11 inhibits ISGF3-induced ISRE promoter activity. This provided further support for the notion that the ability of PRRSV nsp11 to block type I IFN signaling is independent of its endoribonuclease activity and cell cytotoxicity, because these three mutants had similar effects with respect to inhibiting the formation and nuclear translocation of ISGF3 compared with WT nsp11.

title:
  Porcine Reproductive and Respiratory Syndrome Virus nsp11 Antagonizes Type I Interferon Signaling by Targeting IRF9

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) is an arterivirus from the Nidovirales order that causes reproductive failure and respiratory disease in pigs and poses a constant threat to the global pig industry. The PRRSV-encoded nonstructural protein 11 (nsp11) is a nidovirus-specific endoribonuclease (NendoU) that is conserved throughout the Arteriviridae and Coronaviridae families. Previously, our research and that of others demonstrated that PRRSV nsp11 inhibits type I interferon (IFN) production through NendoU activity-dependent mechanisms. Here, we found that PRRSV nsp11 also inhibited IFN-stimulated response element (ISRE) promoter activity and subsequent transcription of IFN-stimulated genes (ISGs). Detailed analysis showed that nsp11 targeted interferon regulatory factor 9 (IRF9), but not transducer and activator of transcription 1 (STAT1) or STAT2, key molecules in the type I IFN signaling pathway. Furthermore, the nsp11-IRF9 interaction impaired the formation and nuclear translocation of the transcription factor complex IFN-stimulated gene factor 3 (ISGF3) in both nsp11-overexpressed and PRRSV-infected cells. Importantly, nsp11 mutations (H129A, H144A, and K173A) that ablate NendoU activity or its cell cytotoxicity also interacted with IRF9 and retained the ability to block IFN signaling, indicating that the nsp11-IRF9 interaction is independent of NendoU activity or cell cytotoxicity of nsp11. Taking the results together, our study demonstrated that PRRSV nsp11 antagonizes type I IFN signaling by targeting IRF9 via a NendoU activity-independent mechanism, and this report describes a novel strategy evolved by PRRSV to counteract host innate antiviral responses, revealing a potential new function for PRRSV nsp11 in type I IFN signaling. IMPORTANCE The nidovirus-specific endoribonuclease (NendoU) encoded by PRRSV nonstructural protein 11 (nsp11) is a unique NendoU of nidoviruses that infect vertebrates; thus, it is an attractive target for the development of antinidovirus drugs. Previous studies have revealed that the NendoU of nidoviruses, including porcine reproductive and respiratory syndrome virus (PRRSV) and human coronavirus 229E (HCoV-229E), acts as a type I interferon (IFN) antagonist. Here, for the first time, we demonstrated that overexpression of PRRSV nsp11 also inhibits IFN signaling by targeting the C-terminal interferon regulatory factor (IRF) association domain of IRF9. This interaction impaired the ability of IRF9 to form the transcription factor complex IFN-stimulated gene factor 3 (ISGF3) and to act as a signaling protein of IFN signaling. Collectively, our data identify IRF9 as a natural target of PRRSV NendoU and reveal a novel mechanism evolved by an arterivirus to counteract innate immune signaling.


id: cord-335706-lopcb77c
author: Tan, Feifei
date: 2011-03-24
url: https://api.elsevier.com/content/article/pii/S0168170211001018
doi: 10.1016/j.virusres.2011.03.011
title:
  Identification of non-essential regions in nucleocapsid protein of porcine reproductive and respiratory syndrome virus for replication in cell culture

abstract:
  Nucleocapsid (N) protein of porcine reproductive and respiratory syndrome virus (PRRSV) plays a central role in virus replication. In this study, serial N- and C-terminal truncations of N protein were performed in the context of type 2 PRRSV infectious cDNA clone, and our results revealed that a stretch of inter-genotypic variable N terminal residues aa 5–13 ((5)NGKQQKKK(13)K) and the last four inter-genotypic variable aa residues ((120)SPS(123)A) at the C terminus of N protein were dispensable for type 2 PRRSV infectivity. All the recovered deletion mutant viruses had spontaneous mutations in the N coding region, including substitution, deletion and insertion. We re-engineered the additional internal deletion with or without the original C-terminal deletion back into wild-type APRRS and found that the internal domain spanning the inter-genotypic variable residues 39–42 ((39)KGP(42)G) and conserved residues 48–52 ((48)KNPE(52)K), respectively, were dispensable for type 2 PRRSV viability. These results demonstrated that N protein contains non-essential regions for virus viability in cell culture. Such dispensable regions could be utilized as insertion site for foreign tag expression and the rescued viruses could be the candidates for marker vaccine.


id: cord-335955-2bw2sly8
author: Shi, Yuejun
date: 2016-04-14
url: https://doi.org/10.1128/jvi.03065-15
doi: 10.1128/jvi.03065-15
title:
  A Dimerization-Dependent Mechanism Drives the Endoribonuclease Function of Porcine Reproductive and Respiratory Syndrome Virus nsp11

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) RNA endoribonuclease nsp11 belongs to the XendoU superfamily and plays a crucial role in arterivirus replication. Here, we report the first crystal structure of the arterivirus nsp11 protein from PRRSV, which exhibits a unique structure and assembles into an asymmetric dimer whose structure is completely different from the hexameric structure of coronavirus nsp15. However, the structures of the PRRSV nsp11 and coronavirus nsp15 catalytic domains were perfectly superimposed, especially in the “active site loop” (His129 to His144) and “supporting loop” (Val162 to Thr179) regions. Importantly, our biochemical data demonstrated that PRRSV nsp11 exists mainly as a dimer in solution. Mutations of the major dimerization site determinants (Ser74 and Phe76) in the dimerization interface destabilized the dimer in solution and severely diminished endoribonuclease activity, indicating that the dimer is the biologically functional unit. In the dimeric structure, the active site loop and supporting loop are packed against one another and stabilized by monomer-monomer interactions. These findings may help elucidate the mechanism underlying arterivirus replication and may represent great potential for the development of antiviral drugs. IMPORTANCE Porcine reproductive and respiratory syndrome virus (PRRSV) is a member of the family Arteriviridae, order Nidovirales. PRRSV is a major agent of respiratory diseases in pigs, causing tremendous economic losses to the swine industry worldwide. The PRRSV nsp11 endoribonuclease plays a vital role in arterivirus replication, but its precise roles and mechanisms of action are poorly understood. Here, we report the first dimeric structure of the arterivirus nsp11 from PRRSV at 2.75-Å resolution. Structural and biochemical experiments demonstrated that nsp11 exists mainly as a dimer in solution and that nsp11 may be fully active as a dimer. Mutagenesis and structural analysis revealed NendoU active site residues, which are conserved throughout the order Nidovirales (families Arteriviridae and Coronaviridae) and the major determinants of dimerization (Ser74 and Phe76) in Arteriviridae. Importantly, these findings may provide a new structural basis for antiviral drug development.


id: cord-340422-8f5xe4zc
author: Rowland, R. R. R.
date: 2001
url: https://www.ncbi.nlm.nih.gov/pubmed/11338389/
doi: 10.1007/s007050170161
title:
  Inhibition of porcine reproductive and respiratory syndrome virus by interferon-gamma and recovery of virus replication with 2-aminopurine

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) belongs to a group of RNA viruses that establish persistent infections. A proposed strategy for evading immunity during persistent PRRSV infection is by preventing the induction of IFN activity in pigs and/or by blocking the activation of antiviral proteins in permissive cells. IFN-γ mRNA expression was observed in the lymph nodes and lungs of pigs infected with wild-type PRRSV strain SDSU-23983. Pretreatment of MARC-145 cells with IFN-γ inhibited wild-type (SDSU-23983 P6) and culture-adapted (SDSU-23983 P136) PRRS viruses in a dose-dependent manner and at relatively low concentrations. The effect of IFN-γ on virus replication included reductions in the number of infected cells, virus yield, and RNA content in single cells. Virus replication was partially restored by the addition of 2-aminopurine (2-AP), an inhibitor of dsRNA inducible protein kinase (PKR). The addition of 2-AP also restored the viral RNA content per cell to near normal levels, suggesting that inhibition of viral RNA synthesis was through PKR. The principal difference between P6 and P136 isolates was the recovery of P136 replication with lower concentrations of 2-AP. Immunostaining with anti-PKR antibody showed a redistribution of PKR from the cytoplasm into nucleoli of infected cells.


id: cord-342276-zrsnahi7
author: Sun, Ying
date: 2011-12-16
txt: ./txt/cord-342276-zrsnahi7.txt
cache: ./cache/cord-342276-zrsnahi7.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/22173307/
doi: 10.1007/s11427-011-4236-0
summary:
  title: Cellular membrane cholesterol is required for porcine reproductive and respiratory syndrome virus entry and release in MARC-145 cells In this study, the role of the plasma membrane cholesterol in porcine reproductive and respiratory syndrome virus (PRRSV) infection of MARC-145 cells was investigated. Previous studies demonstrated that plasma membrane cholesterol plays an important role in the entry and infection processes of many viruses, especially in some enveloped viruses [21] , including Human immunodeficiency virus type 1 (HIV-1) [22] , Poliovirus [23] , Murine coronavirus [24] , Vaccinia virus [25] , Herpes simplex virus [26] , Foot-and-mouth disease virus [27] , and Severe acute respiratory syndrome-related coronavirus (SARS-CoV) [28] . Altogether, these data indicated that cellular membrane cholesterol was required for PRRSV entry into MARC-145 cells, and its depletion by MβCD mainly affects virus attachment, rather than penetration.

title:
  Cellular membrane cholesterol is required for porcine reproductive and respiratory syndrome virus entry and release in MARC-145 cells

abstract:
  Cholesterol represents one of the key constituents of small, dynamic, sterol- and sphingolipid-enriched domains on the plasma membrane. It has been reported that many viruses depend on plasma membrane cholesterol for efficient infection. In this study, the role of the plasma membrane cholesterol in porcine reproductive and respiratory syndrome virus (PRRSV) infection of MARC-145 cells was investigated. Pretreatment of MARC-145 cells with methyl-β-cyclodextrin (MβCD), a drug used to deplete cholesterol from cellular membrane, significantly reduced PRRSV infection in a dose-dependent manner. This inhibition was partially reversed by supplementing exogenous cholesterol following MβCD treatment, suggesting that the inhibition of PRRSV infection was specifically mediated by removal of cellular cholesterol. Further detailed studies showed that depletion of cellular membrane cholesterol significantly inhibited virus entry, especially virus attachment and release. These results indicate that the presence of cholesterol in the cellular membrane is a key component of PRRSV infection.


id: cord-344410-yo9libo0
title: Mutational analysis of the SDD sequence motif of a PRRSV RNA-dependent RNA polymerase
author: Zhou, Yan
date: 2011-09-16
url: https://www.ncbi.nlm.nih.gov/pubmed/21922433/
doi: 10.1007/s11427-011-4216-4
abstract:
  The subgenomic mRNA transcription and genomic replication of the porcine reproductive and respiratory syndrome virus (PRRSV) are directed by the viral replicase. The replicase is expressed in the form of two polyproteins and is subsequently processed into smaller nonstructural proteins (nsps). nsp9, containing the viral replicase, has characteristic sequence motifs conserved among the RNA-dependent RNA polymerases (RdRp) of positive-strand (PS) RNA viruses. To test whether the conserved SDD motif can tolerate other conserved motifs of RNA viruses and the influence of every residue on RdRp catalytic activity, many amino acids substitutions were introduced into it. Only one nsp9 substitution, of serine by glycine (S3050G), could rescue mutant viruses. The rescued virus was genetically stable. Alteration of either aspartate residue was not tolerated, destroyed the polymerase activity, and abolished virus transcription, but did not eliminate virus replication. We also found that the SDD motif was essentially invariant for the signature sequence of PRRSV RdRp. It could not accommodate other conserved motifs found in other RNA viral polymerases, except the GDD motif, which is conserved in all the other PS RNA viruses. These findings indicated that nidoviruses are evolutionarily related to other PS RNA viruses. Our studies support the idea that the two aspartate residues of the SDD motif are critical and essential for PRRSV transcription and represent a sequence variant of the GDD motif in PS RNA viruses.


id: cord-344740-st2yw090
author: Lee, Changhee
date: 2004-12-08
url: https://www.sciencedirect.com/science/article/pii/S016524270400251X
doi: 10.1016/j.vetimm.2004.09.020
title:
  Differential host cell gene expression regulated by the porcine reproductive and respiratory syndrome virus GP4 and GP5 glycoproteins

abstract:
  The porcine reproductive and respiratory syndrome virus (PRRSV) GP4 and GP5 proteins are two membrane-associated viral glycoproteins that have been shown to induce neutralizing antibodies. In the present study, the host cell gene expression profiles altered by the GP4 and GP5 proteins were investigated by the use of DNA microarrays. Sublines of Marc-145 and HeLa cells were established by stable transfection with open reading frame (ORF)4 and ORF5 of PRRSV, respectively, and differential gene expressions were studied using microarray chips embedded with 1718 human-expressed sequence tags. The genes for protein degradation, protein synthesis and transport, and various other biochemical pathways were identified. No genes involved in the apoptosis pathway appeared to be regulated in GP5-expressing cells. The microarray data may provide insights into the specific cellular responses to the GP4 and GP5 proteins during PRRSV infection.


id: cord-344953-gtg12hiu
author: Prather, Randall S.
date: 2017-10-17
url: https://doi.org/10.1038/s41598-017-13794-2
doi: 10.1038/s41598-017-13794-2
title:
  Knockout of maternal CD163 protects fetuses from infection with porcine reproductive and respiratory syndrome virus (PRRSV)

abstract:
  After infection of the porcine dam at about 90 days of gestation, porcine reproductive and respiratory syndrome virus (PRRSV) crosses the placenta and begins to infect fetuses. Outcomes of include abortion, fetal death and respiratory disease in newborn piglets. CD163 is the receptor for the virus. In this study, CD163-positive fetuses, recovered between 109 days of gestation or 20 days after maternal infection, were completely protected from PRRSV in dams possessing a complete knockout of the CD163 receptor. The results demonstrate a practical means to eliminate PRRSV-associated reproductive disease, a major source of economic hardship to agriculture.


id: cord-345516-fgn7rps3
author: Miller, Laura C
date: 2012-10-30
url: https://doi.org/10.1186/1746-6148-8-208
doi: 10.1186/1746-6148-8-208
title:
  Analysis of the swine tracheobronchial lymph node transcriptomic response to infection with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus

abstract:
  BACKGROUND: Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen of swine worldwide. Emergence in 2006 of a novel highly pathogenic PRRSV (HP-PRRSV) isolate in China necessitated a comparative investigation into the host transcriptome response in tracheobronchial lymph nodes (TBLN) 13 days post-infection with HP-PRRSV rJXwn06, PRRSV strain VR-2332 or sham inocula. RNA from each was prepared for next-generation sequencing. Amplified library constructs were directly sequenced and a list of sequence transcripts and counts was generated using an RNAseq analysis pipeline to determine differential gene expression. Transcripts were annotated and relative abundance was calculated based upon the number of times a given transcript was represented in the library. RESULTS: Major changes in transcript abundance occurred in response to infection with either PRRSV strain, each with over 630 differentially expressed transcripts. The largest increase in transcript level for either virus versus sham-inoculated controls were three serum amyloid A2 acute-phase isoforms. However, the degree of up or down-regulation of transcripts following infection with HP-PRRSV rJXwn06 was greater than transcript changes observed with US PRRSV VR-2332. Also, of 632 significantly altered transcripts within the HP-PRRSV rJXwn06 library 55 were up-regulated and 69 were down-regulated more than 3-fold, whilst in the US PRRSV VR-2332 library only 4 transcripts were up-regulated and 116 were down-regulated more than 3-fold. CONCLUSIONS: The magnitude of differentially expressed gene profiles detected in HP-PRRSV rJXwn06 infected pigs as compared to VR-2332 infected pigs was consistent with the increased pathogenicity of the HP-PRRSV in vivo.


id: cord-350626-ov9fy10b
author: Nazki, Salik
date: 2020-05-13
url: https://doi.org/10.1186/s13567-020-00789-7
doi: 10.1186/s13567-020-00789-7
title:
  Evaluation of local and systemic immune responses in pigs experimentally challenged with porcine reproductive and respiratory syndrome virus

abstract:
  The host-associated defence system responsible for the clearance of porcine reproductive and respiratory syndrome virus (PRRSV) from infected pigs is currently poorly understood. To better understand the dynamics of host–pathogen interactions, seventy-five of 100 pigs infected with PRRSV-JA142 and 25 control pigs were euthanized at 3, 10, 21, 28 and 35 days post-challenge (dpc). Blood, lung, bronchoalveolar lavage (BAL) and bronchial lymph node (BLN) samples were collected to evaluate the cellular immune responses. The humoral responses were evaluated by measuring the levels of anti-PRRSV IgG and serum virus-neutralizing (SVN) antibodies. Consequently, the highest viral loads in the sera and lungs of the infected pigs were detected between 3 and 10 dpc, and these resulted in moderate to mild interstitial pneumonia, which resolved accompanied by the clearance of most of the virus by 28 dpc. At peak viremia, the frequencies of alveolar macrophages in infected pigs were significantly decreased, whereas the monocyte-derived DC/macrophage and conventional DC frequencies were increased, and these effects coincided with the early induction of local T-cell responses and the presence of proinflammatory cytokines/chemokines in the lungs, BAL, and BLN as early as 10 dpc. Conversely, the systemic T-cell responses measured in the peripheral blood mononuclear cells were delayed and significantly induced only after the peak viremic stage between 3 and 10 dpc. Taken together, our results suggest that activation of immune responses in the lung could be the key elements for restraining PRRSV through the early induction of T-cell responses at the sites of virus replication.


id: cord-351881-qea4b0i5
author: Eck, Melanie
date: 2016-02-19
txt: ./txt/cord-351881-qea4b0i5.txt
cache: ./cache/cord-351881-qea4b0i5.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/26895704/
doi: 10.1186/s13567-016-0318-0
summary:
  title: Virus replicon particles expressing porcine reproductive and respiratory syndrome virus proteins elicit immune priming but do not confer protection from viremia in pigs However, none of the PRRSV antigens expressed from VRP, with the exception of the N protein, did induce any detectable antibody response in pigs before challenge infection with PRRSV. These data show that the VSV replicon vector can induce immune responses to heterologous proteins in pigs, but that the PRRSV envelope proteins expressed from VSV VRP are poorly immunogenic. Again, before challenge infection, vaccination with VRP expressing the structural proteins of PRRSV did not induce any detectable antibody response against GP5, GP4 and GP3 as measured by ELISA (not shown). Following challenge infection, GP5-specific antibody responses were detected on day 7 pi in 2 out of 4 pigs, and all pigs vaccinated with VRP expressing the PRRSV proteins seroconverted to GP5 at day 11 pi (Table 3 ).

title:
  Virus replicon particles expressing porcine reproductive and respiratory syndrome virus proteins elicit immune priming but do not confer protection from viremia in pigs

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) is the causative agent of one of the most devastating and economically significant viral disease of pigs worldwide. The vaccines currently available on the market elicit only limited protection. Recombinant vesicular stomatitis virus (VSV) replicon particles (VRP) have been used successfully to induce protection against influenza A virus (IAV) in chickens and bluetongue virus in sheep. In this study, VSV VRP expressing the PRRSV envelope proteins GP5, M, GP4, GP3, GP2 and the nucleocapsid protein N, individually or in combination, were generated and evaluated as a potential vector vaccine against PRRSV infection. High level expression of the recombinant PRRSV proteins was demonstrated in cell culture. However, none of the PRRSV antigens expressed from VRP, with the exception of the N protein, did induce any detectable antibody response in pigs before challenge infection with PRRSV. After challenge however, the antibody responses against GP5, GP4 and GP3 appeared in average 2 weeks earlier than in pigs vaccinated with the empty control VRP. No reduction of viremia was observed in the vaccinated group compared with the control group. When pigs were co-vaccinated with VRP expressing IAV antigens and VRP expressing PRRSV glycoproteins, only antibody responses to the IAV antigens were detectable. These data show that the VSV replicon vector can induce immune responses to heterologous proteins in pigs, but that the PRRSV envelope proteins expressed from VSV VRP are poorly immunogenic. Nevertheless, they prime the immune system for significantly earlier B-cell responses following PRRSV challenge infection.


id: cord-352967-y1fyke9u
author: Jiang, Yunbo
date: 2010-07-31
txt: ./txt/cord-352967-y1fyke9u.txt
cache: ./cache/cord-352967-y1fyke9u.txt
extension: .txt
mime: text/plain
url: https://www.ncbi.nlm.nih.gov/pubmed/20676761/
doi: 10.1007/s11259-010-9435-9
summary:
  In this study, we investigated the inhibitory effect of NO on the infection by porcine reproductive and respiratory syndrome virus (PRRSV) in vitro and the role of NO in the defense against PRRSV. We found that the maximal inhibition effect of NAP on PRRSV replication was achieved upon treatment 1 h after virus infection and the virus yield was reduced by approximately 50 fold in the presence of 400 μM NAP. To date, NAP is only used as the negative control for SNAP to study the inhibitory effect of NO on virus replication in previous studies, and its antiviral activity was not reported. Unexpectedly, NAP, the "commonly used" negative control for NO-donor SNAP had a significant antiviral activity against PRRSV replication (Fig. 1a ) at low infectious dose (MOI=0.05). The inhibitory effect of NAP in Marc-145 cells was investigated by determining the kinetics of PRRSV production under different NAP treatments.

title:
  N-acetylpenicillamine inhibits the replication of porcine reproductive and respiratory syndrome virus in vitro

abstract:
  Nitric oxide (NO) was proposed to be an important molecule against some microorganisms. In this study, we investigated the inhibitory effect of NO on the infection by porcine reproductive and respiratory syndrome virus (PRRSV) in vitro and the role of NO in the defense against PRRSV. Our results indicated that exogenous NO did not inhibit PRRSV infection. Unexpectedly, N-acetylpenicillamine (NAP), a commonly used compound as negative control for NO-producing reagents, inhibited PRRSV replication. Thus, the inhibition effect of NAP on PRRSV replication was further explored. We found that the maximal inhibition effect of NAP on PRRSV replication was achieved upon treatment 1 h after virus infection and the virus yield was reduced by approximately 50 fold in the presence of 400 μM NAP. An obvious inhibitory effect on viral RNA and protein synthesis was also observed. However, the inhibitory effect was only achieved at early phase of virus infection. The normal virus yield could be restored upon the removal of NAP treatment. The inhibitory effect might be caused by sulfhydryl-reducing capacity and metal chelating properties of NAP. These studies suggested that (i) NO production or NO synthase (NOS) expression profiling may not be a reliable index for the immune response to PRRSV; (ii) NAP could inhibit the replication of PRRSV.


id: cord-353703-u86ggw11
author: Gao, Peng
date: 2019-11-18
url: https://www.ncbi.nlm.nih.gov/pubmed/31738790/
doi: 10.1371/journal.ppat.1008169
title:
  Reprogramming the unfolded protein response for replication by porcine reproductive and respiratory syndrome virus

abstract:
  The unfolded protein response (UPR) in the endoplasmic reticulum (ER) constitutes a critical component of host innate immunity against microbial infections. In this report, we show that porcine reproductive and respiratory syndrome virus (PRRSV) utilizes the UPR machinery for its own benefit. We provide evidence that the virus targets the UPR central regulator GRP78 for proteasomal degradation via a mechanism that requires viral glycoprotein GP2a, while both IRE1-XBP1s and PERK-eIF2α-ATF4 signaling branches of the UPR are turned on at early stage of infection. The activated effector XBP1s was found to enter the nucleus, but ATF4 was unexpectedly diverted to cytoplasmic viral replication complexes by means of nonstructural proteins nsp2/3 to promote viral RNA synthesis. RNAi knockdown of either ATF4 or XBP1s dramatically attenuated virus titers, while overexpression caused increases. These observations reveal attractive host targets (e.g., ATF4 and XBP1s) for antiviral drugs and have implications in vaccine development.


id: cord-354730-hfau2odb
author: Wang, Rong
date: 2014-07-03
url: https://www.ncbi.nlm.nih.gov/pubmed/25101271/
doi: 10.1155/2014/315470
title:
  Antagonizing Interferon-Mediated Immune Response by Porcine Reproductive and Respiratory Syndrome Virus

abstract:
  Interferons (IFNs) are important components in innate immunity involved in the first line of defense to protect host against viral infection. Porcine reproductive and respiratory syndrome virus (PRRSV) leads to severe economic losses for swine industry since being first identified in early 1990s. PRRSV interplays with host IFN production and IFN-activated signaling, which may contribute to the delayed onset and low level of neutralizing antibodies, as well as weak cell-mediated immune response in infected pigs. PRRSV encodes several proteins that act as antagonists for the IFN signaling. In this review, we summarized the various strategies used by PRRSV to antagonize IFN production and thwart IFN-activated antiviral signaling, as well as the variable interference with IFN-mediated immune response by different PRRSV strains. Thorough understanding of the interaction between PRRSV and host innate immune response will facilitate elucidation of PRRSV pathogenesis and development of a better strategy to control PRRS.


id: cord-356197-js7l86fh
author: Zhou, Ping
date: 2011-08-07
url: https://www.ncbi.nlm.nih.gov/pubmed/21850204/
doi: nan
title:
  Molecular Characterization of Transcriptome-wide Interactions between Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus and Porcine Alveolar Macrophages in vivo

abstract:
  Porcine reproductive and respiratory syndrome virus (PRRSV) infects mainly the porcine alveolar macrophages (PAMs) and causes porcine reproductive and respiratory syndrome (PRRS). Previous studies have analyzed the global gene expression profiles of lung tissue in vivo and PAMs in vitro following infection with PRRSV, however, transcriptome-wide understanding of the interaction between highly pathogenic PRRSV (HP-PRRSV) and PAMs in vivo has not yet been established. In this study, we employed Affymetrix microarrays to investigate the gene expression patterns of PAMs isolated from Tongcheng piglets (a Chinese indigenous breed) after infection with HP-PRRSV. During the infection, Tongcheng piglets exhibited typical clinical signs, e.g. fever, asthma, coughing, anorexia, lethargy and convulsion, but displayed mild regional lung damage at 5 and 7 dpi. Microarray analysis revealed that HP-PRRSV infection has affected PAMs in expression of the important genes involved in cytoskeleton and exocytosis organization, protein degradation and folding, intracellular calcium and zinc homeostasis. Several potential antiviral strategies might be employed in PAMs, including upregulating IFN-induced genes and increasing intracellular zinc ion concentration. And inhibition of the complement system likely attenuated the lung damage during HP-PRRSV infection. Transcriptomic analysis of PAMs in vivo could lead to a better understanding of the HP-PRRSV-host interaction, and to the identification of novel antiviral therapies and genetic components of swine tolerance/susceptibility to HP-PRRS.


