id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-253656-2x4y403o	Ren, Wenlin	Recombinant SARS-CoV-2 spike S1-Fc fusion protein induced high levels of neutralizing responses in nonhuman primates	2020-06-24		.txt	text/plain	3645	202	60	In this study, we examined the immunogenicity of CHO-expressed recombinant SARS-CoV-2 S1-Fc fusion protein in mice, rabbits, and monkeys as a potential candidate for a COVID-19 vaccine. Most importantly, in less than 20 days and three injections of the S1-Fc fusion protein, two monkeys developed higher virus neutralizing titers than a recovered COVID-19 patient in a live SARS-CoV-2 infection assay. The sera were collected on Day 38 and evaluated by ELISA against SARS-CoV-2 S1-6His protein using HRP-conjugated goat anti-mouse IgG Fc-specific secondary antibodies. As shown in Table 1 and Fig. 5A , immunization of SARS-CoV-2 S1-Fc fusion protein with AD20Gold + as adjuvant also induced very high neutralizing activities with IC50 titers >3000 and IC90 titers around 440-501 in both rabbits on Day 27 after immunizations. Beside high levels of the anti-S1 antibodies elicited, higher neutralizing activities against live SARS-CoV-2 virus and/or pseudovirus from the anti-sera of macaques and rabbits.	./cache/cord-253656-2x4y403o.txt	./txt/cord-253656-2x4y403o.txt