key: cord-0298058-ac5qn40o
authors: Seidel, A.; Jahrsdörfer, B.; Körper, S.; Albers, D.; von Maltitz, P.; Müller, R.; Lotfi, R.; Wuchter, P.; Klüter, H.; Schmidt, M.; Münch, J.; Schrezenmeier, H.
title: SARS-CoV-2 vaccination of convalescents boosts neutralization capacity against SARS-CoV-2 Delta and Omicron that can be predicted by anti-S antibody concentrations in serological assays
date: 2022-01-17
journal: nan
DOI: 10.1101/2022.01.17.22269201
sha: 9c4a5f9cff18ffc0a64c7780fbae25bea3f93ea6
doc_id: 298058
cord_uid: ac5qn40o

Background : Recent data on immune evasion of new SARS-CoV-2 variants raise concerns about antibody-based COVID-19 therapies. Therefore in this study the in-vitro neutralization capacity against SARS-CoV-2 variants Wuhan D614G, Delta and Omicron in sera of convalescent individuals with and without boost by vaccination was assessed. Methods and Findings: This in-vitro study included 66 individuals with a history of SARS-CoV-2 infection, divided into subgroups without (n=29) and with SARS-CoV-2 vaccination (n=37). We measured SARS-CoV-2 antibody concentrations by serological assays (anti-SARS-CoV-2-QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S) and neutralizing titers against Wuhan D614G, Delta and Omicron in a pseudovirus neutralization assay. Sera of the majority of unvaccinated convalescents did not effectively neutralize Delta and Omicron (4/29, 13.8% and 19/29, 65.5%, resp.). Neutralizing titers against Wuhan D614G, Delta and Omicron were significantly higher in vaccinated compared to unvaccinated convalescents (p<0.0001) with 11.1, 15.3 and 60-fold higher geometric mean of 50%-neutralizing titers (NT50) in vaccinated compared to unvaccinated convalescents. The increase in neutralizing titers was already achieved by one vaccination dose. Neutralizing titers were highest in the first 3 months after vaccination. Concentrations of anti-S antibodies in the serological assays anti-SARS-CoV-2 QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S predict neutralization capacity against Wuhan D614G, Delta and Omicron. While Wuhan D614G was neutralized in-vitro by Bamlanivimab, Casirivimab and Imdevimab, Omicron was resistant to these monoclonal antibodies. Conclusions: These findings confirm substantial immune evasion of Delta and Omicron which can be overcome by vaccination of convalescents. This informs strategies for choosing of plasma donors in COVID-19 convalescent plasma programs that shall select specifically vaccinated convalescents with very high titers of anti-S antibodies.

Sera of the majority of unvaccinated convalescents did not effectively neutralize Delta and Omicron (4/29, 48 13.8% and 19/29, 65.5%, resp.). Neutralizing titers against Wuhan D614G, Delta and Omicron were 49 significantly higher in vaccinated compared to unvaccinated convalescents (p<0.0001) with 11.1, 15.3 and 50 60-fold higher geometric mean of 50%-neutralizing titers (NT50) in vaccinated compared to unvaccinated 51 convalescents. The increase in neutralizing titers was already achieved by one vaccination dose. 52

Neutralizing titers were highest in the first 3 months after vaccination. Concentrations of anti-S antibodies 53 in the serological assays anti-SARS-CoV-2 QuantiVac-ELISA (IgG) and Elecsys Anti-SARS-CoV-2 S predict 54 neutralization capacity against Wuhan D614G, Delta and Omicron. While Wuhan D614G was neutralized 55 in-vitro by Bamlanivimab, Casirivimab and Imdevimab, Omicron was resistant to these monoclonal 56 antibodies. 57

These findings confirm substantial immune evasion of Delta and Omicron which can be overcome by 59 vaccination of convalescents. This informs strategies for choosing of plasma donors in COVID-19 60 convalescent plasma programs that shall select specifically vaccinated convalescents with very high titers 61

The B.1.1.529 variant was first reported to the World Health Organization from South Africa on 24 64

November 2021 (1) and has been classified as a variant of concern (VOC), named Omicron (1) . 65

The role of passive immune therapy of COVID-19 by convalescent plasma (CCP) is still under investigation. 66

Data suggest efficacy of CCP in early intervention (2-6), in particular among seronegative patients and 67

immunosuppressed patients (7-9). A significant antibody dose response has been observed in some of the 68 CCP trials (3;4;10;11). Omicron might escape passive immune therapy since it can evade neutralization by 69 sera from vaccinated and convalescent individuals and by monoclonal antibodies in-vitro (12-16) and the 70 risk of reinfection with Omicron is higher compared to other VOC (12). 71

In this study, we assessed the neutralization capacity of sera from convalescents, some but not all of which 72 were vaccinated, against the Wuhan D614G, Delta and Omicron variants. The question was whether 73 superimmunized individuals, i.e. vaccinated convalescents, had cross-neutralization capacity against 74

Omicron sufficient to be considered as plasma donors for passive immune therapy. 75 . CC-BY 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint Biology Unit, German Primate Center, Göttingen, Germany) by Transit LT-1 (Mirus). One day after 88 transfection, cells were inoculated with a replication-deficient vesicular stomatitis virus (VSV) vector in 89 which the genetic information for its native glycoprotein (VSV-G) is replaced by genes encoding enhanced 90 green fluorescent protein and firefly luciferase (FLuc) (kindly provided by Gert Zimmer, Institute of 91 Virology and Immunology, Mittelhäusern, Switzerland), and incubated for 2 h at 37°C. Then the inoculum 92 was removed, cells were washed with PBS and fresh medium containing anti-VSV-G antibody (I1-93 hybridoma cells; ATCC no. CRL-2700) added to block remaining VSV-G carrying particles. After 16-18 h, 94 supernatants were collected and centrifuged (2,000 x g, 10 min, room temperature) to clear cellular 95 debris. Samples were then aliquoted and stored at -80°C. 96

The pseudovirus neutralization experiments were performed as previously described (18) In brief, Vero 98 E6 cells were seeded in 96-well plates one day prior (6,000 cells/well, 2.5% FCS. Heat-inactivated (56°C, 99 30 min) sera were serially titrated (4-fold titration series with 7 steps + buffer only control) in PBS, 100 . CC-BY 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted January 17, 2022. ; https://doi.org/10.1101/2022.01.17.22269201 doi: medRxiv preprint

We studied a cohort of 66 individuals with a history of a SARS-CoV-2 infection ( Table 1) . The cohort has 117 been subdivided in a group without vaccination (n=29) and a group with vaccination (n=37). 118

Non-vaccinated individuals with a history of infection exhibited Wuhan D614G neutralizing titers of 249 119 (geometric mean neutralizing (GMN) titers, 95% confidence interval (95%-CI) 162-381) (Fig.1A) . Wuhan D614G, 15.3-fold for Delta and 60-fold for Omicron (Fig.1A) . Neutralizing titers against Wuhan 127 D614G and Omicron did no longer differ significantly in convalescents after vaccination (Fig.1A) . For all 128 three variants, neutralizing titers were not significantly different between subjects who received either 129 one or two vaccinations, resp. (Fig.1B) . Neutralizing titers against Wuhan D614G and Delta were 130 significantly higher among those with an interval ≤ 90 days since the last vaccination dose as compared to 131 intervals >90 days, while for Omicron no such significant difference was found (Fig.1C) . The geometric 132 means of NT50 against Wuhan D614G were 4741 (≤90 days) and 1644 (>90 days)(p=0.0326), against Delta 133 1496 (≤90 days)) and 501 (>90 days)(p=0.0202), and against Omicron 1953 (≤90 days)) and 843 (>90 134 days)(p=0.1352). While in the pseudovirus neutralization assay Omicron was neutralized in-vitro by the 135 polyvalent antibodies of convalescent, vaccinated individuals (Fig.1A) , it was resistant to the monoclonal 136 antibodies Bamlanivimab, Casirivimab and Imdevimab (Fig.1D) . 137

The correlation matrix of NT50 against Wuhan D614G, Delta and Omicron, the -QuantiVac-ELISA (IgG) 138 ELISA and the Elecsys Anti-SARS-CoV-2 S revealed good correlations between all five assays, in particular 139 between the two anti-SARS-CoV-2 serological assays (Spearman correlation 0.95) and the NT50 against 140 Wuhan D614G and Delta (Spearman correlation 0.93) (Fig.2) . Spearman correlation between anti-SARS-141 . CC-BY 4.0 International license It is made available under a perpetuity.

is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted January 17, 2022. ; https://doi.org/10.1101/2022.01.17.22269201 doi: medRxiv preprint

CoV-2-QuantiVac-ELISA (IgG) and NT50 against Omicron or Delta was 0.88 and 0.94 ( Fig.3A and Fig.3C) . 142

The Spearman correlation between Elecsys Anti-SARS-CoV-2 S and NT50 against Omicron and Delta was 143 0.92 and 0.90 ( Fig.3B and Fig.3D) . is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted January 17, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted January 17, 2022. is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted January 17, 2022. ; https://doi.org/10.1101/2022.01.17.22269201 doi: medRxiv preprint is the author/funder, who has granted medRxiv a license to display the preprint in (which was not certified by peer review) preprint

The copyright holder for this this version posted January 17, 2022. 

Correlation between anti-S antibody concentrations measured by anti-SARS-CoV-2-QuantiVac-ELISA (IgG) and NT50 against Omicron (Spearman 231 correlation 0.88). Results of non-vaccinated convalescents (inf) are shown as triangles, and results of vaccinated convalescents (inf + vax) are shown as 232 filled circles. 233

Correlation between anti-S antibody concentrations measured by Elecsys Anti-SARS-CoV-2 S and NT50 against Omicron (Spearman correlation 0.92). 234

Results of non-vaccinated convalescents (inf) are shown as triangles, and results of vaccinated convalescents (inf + vax) are shown as filled circles. 235

Correlation between anti-S antibody concentrations measured by anti-SARS-CoV-2 QuantiVac-ELISA (IgG) and NT50 against Delta (Spearman correlation 236 0.94). Results of non-vaccinated convalescents (inf) are shown as triangles, and results of vaccinated convalescents (inf + vax) are shown as filled circles. 237

Correlation between anti-S antibody concentrations measured by Elecsys Anti-SARS-CoV-2 S and NT50 against Delta (Spearman correlation 0.90). Results 238 of non-vaccinated convalescents (inf) are shown as triangles, and results of vaccinated convalescents (inf + vax) are shown as filled circles. 239 

1 529)-sars-cov-2-variant-of-concern

Early High-Titer Plasma 253 Therapy to Prevent Severe Covid-19 in Older Adults

Convalescent Plasma

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Effect of time and titer in 265 convalescent plasma therapy for COVID-19. iScience

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Use of convalescent 270 plasma in COVID-19 patients with immunosuppression

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Results of the CAPSID 276 randomized trial for high-dose convalescent plasma in patients with severe COVID-19

A 279 randomized double-blind controlled trial of convalescent plasma in adults with severe COVID-19

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Reduced Neutralization of 285 SARS-CoV-2 Omicron Variant by Vaccine Sera and monoclonal antibodies

Striking antibody evasion manifested by 288 the Omicron variant of SARS-CoV-2

Considerable 291 escape of SARS-CoV-2 Omicron to antibody neutralization

Broadly neutralizing 294 antibodies overcome SARS-CoV-2 Omicron antigenic shift

Donors for SARS-CoV-2 297

Convalescent Plasma for a Controlled Clinical Trial: Donor Characteristics, Content and Time 298 Course of SARS-CoV-2 Neutralizing Antibodies

Heterologous ChAdOx1 nCoV-301 19 and BNT162b2 prime-boost vaccination elicits potent neutralizing antibody responses and T 302 cell reactivity against prevalent SARS-CoV-2 variants

Naturally enhanced 304 neutralizing breadth against SARS-CoV-2 one year after infection