Figure 6.

Cross-reactive neutralizing antibody response and challenge virus recovery in hamsters immunized with sa-mRNA S and sa-mRNA S-N vaccines or Adj-Pro S vaccine

(A) Female Syrian hamsters (n = 5) were immunized twice, 3 weeks apart, with 3.0 μg or 0.3 μg of sa-mRNA S (blue) or the sa-mRNA S-N (red) or with 5.0 μg Adj-Pro S (green). Hamsters were challenged 4 weeks after the second dose with live SARS-CoV-2 original virus at 100 50% tissue culture infectious dose (TCID₅₀) per animal and sacrificed 4 days later. Lungs and nasal turbinates were collected for recovery of infectious virus. (B) Serum samples collected at time of challenge were tested in MN assay for original virus, Beta, and Delta 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. Total virus recovery from lung (C) and nasal turbinates (D) expressed as TCID₅₀/g of tissue. Each dot represents an individual sample, and the line 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).