Fig. 5: Potent divalent MR3 protects hamsters against weight loss and viral replication.

a Neutralization assay of MR3-MR3-ABD using pseudovirus bearing the wild-type Spike (614D, black square) or the D614G mutant Spike (614G, red circle). Data are from one representative experiment of three (614 G) or two (614D) independent experiments. Statistics were not performed for 614G because the three experiments were performed with different sybody concentrations. b Neutralization of authentic SARS-CoV-2 by Fc-MR3 (red square) and MR3-MR3-ABD (blue circle) measured using a plaque-reduction assay. Mean ± standard deviation are plotted (n = 3 independent experiments). c Body weights of hamsters treated with antibodies (color-coded as indicated) were measured at the indicated days after inoculation with SARS-CoV-2. Statistics were performed using two-way ANOVA followed by Sidak’s multiple comparisons test. **p < 0.005; ****p < 0.001. Timepoint starting to show significance: PBS vs Fc-MR3 and Fc-Sb2 vs Fc-MR3, 2 dpi; PBS vs MR3-MR3-ABD and Sb92-Sb44-ABD vs MR3-MR3-ABD, 4 dpi. SARS-CoV-2 viral RNA (d, f) or infectious virus (e, g) was detected in the lung (d, e) and the nasal turbinates (f, g). Percentage of inflamed lung tissue (h) and percentage of lung tissue expressing SARS-CoV-2 antigen (i) estimated by microscopic examination in different groups of hamsters at 4 days after SARS-CoV-2 inoculation. In c–i, the mean percentage of starting weight, the mean copy number, the mean infectious titer, or the mean pathology score is shown, error bars represent the standard error of the mean (SEM). n = 5 biologically independent samples. Statistical analyses were performed using one-way ANOVA followed by Tukey’s multiple comparisons test on log-transformed data (d–g) or raw data (h, i). ns not significant; *p < 0.05; **p < 0.01; ****p < 0.0001. Source data of a–i and exact p values of c–i are provided as a Source data file.