Fig. 4: Neutralization potential of serum from vaccinated mice.

A Serum collected 21 days after booster vaccination (day 42) was used in a microneutralization assay against strain WA1/2020 (gray) and Omicron XBB.1 (green). Anti-viral drug remdesivir was used as a positive control. Each symbol represents pooled sera from two animals. The dotted line represents the limit of detection. B, C Serum collected 21 days after booster vaccination (day 42) was tested for the ability to block the binding of soluble human ACE2 to recombinant spike trimers from the indicated strains by multiplex competitive ELISA. Serum was diluted 1:500 in (B), and 1:100 in (C). See also Supplementary Fig. 4 for data with additional Omicron variants. Differences between groups were analyzed by one-way ANOVA with multiple comparisons by Tukey post-test. Asterisks denote significant differences versus unadjuvanted spike antigen and #’s indicate differences between other indicated groups. *^/#p < 0.05, ^##p < 0.01, *^**/###p < 0.001, ****^/####p < 0.0001.