Fig. 7: Prophylactic efficacies of h5B11 against RSV A2 and B18537 infections in cotton rat model.

a RSV titers of lungs and noses in each group of animals five days after 2 × 10⁶ pfu of RSV A2 challenge. Six animals were used per group (n = 6). b RSV titers of lungs and noses in each group of animals five days after 4.8 × 10⁵ pfu of RSV B18537 challenge. Six animals were used per group (n = 6). Error bars represent mean values with SD. The dotted line means the limit of detection. Statistical differences between groups were analyzed by one-way ANOVA, followed by Tukey’s multiple comparisons post hoc test. c–l Histology scores of lungs of cotton rats infected with RSV strain A2 (c–g) and B18573 (h–l), respectively. Blood vessels (perivasculitis; c and h), bronchus (peribronchitis; d and i), bronchioles (peribronchiolitis; e and j), alveolar lumen (alveolitis; f and k) and lung interstitium (interstitial pneumonitis; g and l) in lung tissues were scored ranging from 0 to 4 points, according to the number of layers of inflammatory cells. Error bars represent mean values with SD. m–p To determine EC₅₀ of h5B11 in RSV-challenged cotton rats, the correlations of serum antibody concentrations with viral titers in lungs and noses were analyzed and in vivo EC₅₀ values were calculated using a nonlinear regression analysis. Four to five cotton rats were used per dose group (n = 4–5). Points represent observed data. The solid lines indicate nonlinear regression fit of the inhibitory sigmoidal dose-response model with variable slope for RSV A lung (m), RSV A nose (n), RSV B lung (o), and RSV B nose (p). The sigmoidal dashed lines represent 95% confidence bands. The horizontal dotted lines represent the average pfu/g tissue for the naïve challenged controls. Kruskal-Wallis test was used for statistical differences between groups and corrected for multiple comparisons using Dunn’s method. Source data are provided as a Source Data file.