Figure 3.

Cross-reactive neutralizing antibody responses raised by sa-mRNA S and sa-mRNA S-N vaccines or Adj-Pro S vaccine against original virus in BALB/C and C57BL/6J mice

BALB/c or C57BL/6J female mice (n = 10 each) were immunized twice, 3 weeks apart, with 1.0 μg or 0.01 μg of sa-mRNA S (blue) or sa-mRNA S-N vaccines (red), or 1.0 μg Adj-Pro S vaccine (green). Serum samples were collected at day 43. Sera from BALB/C (A) or C57BL/6J (B) mice were tested in MN assay for the original virus. Sera from BALB/c mice raised by sa-mRNA S (C) and sa-mRNA S-N (D) were tested additionally in MN assay for the original virus (red) and the emerging Alpha (blue), Beta (green), Gamma (purple), and Delta (gray) variants. 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).