Figure 4.

Cross-reactive neutralizing antibody responses raised by sa-mRNA S vaccines against original virus, 614G, and Alpha and Beta variants in BALB/c mice

BALB/c female mice (n = 10) were immunized twice, 3 weeks apart, with 1.0 μg or 0.01 μg of sa-mRNA S against the original virus (blue), 614G (red), Alpha variant (green), or Beta variant (purple). Serum samples were collected at day 43. Sera were tested in MN assay for the original virus (A), Alpha variant (B), Beta variant (C), Gamma variant (D), and Delta variant (E). Each dot represents an individual serum sample, and the column represents the geometric mean for the group. The dotted line in each panel represents the lower limit of quantitation for the assay. Statistical analysis by two-way ANOVA with Tukey’s multiple comparison test was performed using GraphPad Prism 9.1.0. ∗p < 0.05. ∗∗p < 0.01. ∗∗∗p < 0.001. ∗∗∗∗p < 0.0001. ns, not significant (p ≥ 0.05).