Fig. 3: RBD-SpyVLPs induce strong antibody responses in mice that are comparable to the responses in recovered patients. | Nature Communications

Fig. 3: RBD-SpyVLPs induce strong antibody responses in mice that are comparable to the responses in recovered patients.

From: A COVID-19 vaccine candidate using SpyCatcher multimerization of the SARS-CoV-2 spike protein receptor-binding domain induces potent neutralising antibody responses

Fig. 3

C57BL/6 (red) or BALB/c (blue) mice (n = 6 in each group) were dosed twice IM, 2 weeks apart with 0.1 or 0.5 µg purified RBD, RBD-SpyVLP or VLP alone with AddaVax adjuvant added to all. Sera were harvested at 2 weeks after the first dose (open circles) and at 3 weeks after the second dose (closed circles). Sera were analysed in a ELISA against full-length spike glycoprotein b ELISA against RBD, c in an ACE2 competition assay, and d in virus neutralisation assays (VNT) against wild-type SARS-CoV-2 virus. e Antibody response analysed by RBD ELISA for mice dosed twice with 0.5 µg RBD-SpyVLP (pre-lyophilised, post-lyophilised or freeze–thawed five times). Data are presented as the group geometric means ± 95% confidence intervals. COVID-19 convalescent plasma from humans with mild (open mauve circles) or critical/severe disease (closed mauve circles) were included for comparison. Differences between dosing groups were determined by Kruskal–Wallis test followed by Dunn’s multiple comparison test. Two-tailed Mann–Whitney U test was used to compare the immunised groups against convalescent human plasma. Dotted lines represent the lowest mouse sera dilutions tested. Bold dotted line represents the lowest human sera dilution tested. Source data are provided as a Source Data file.

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