Fig 2. Effect of prophylactic administration of 2KD1+3B2 VHH on RVA-induced diarrhea and host humoral immune response against RVA.

All mice were orally inoculated with 1778 DD₅₀ of ECw RVA at day four of life (PID 0), as indicated by the arrow. Mice were euthanized sequentially to obtain intestinal tissue (3–4 mice per time point). Graphics on the left side of the panels depict intestinal infectious RVA titers (by CCIF) and diarrhea prevalence. Blue lines show the development of intestinal RVA disease whereas vertical bars show the mean percentage of mice with diarrhea per group. The * symbol indicates that the percentage of mice with diarrhea was significantly lower than in the untreated control group (Fisher Exact test). The thin horizontal line indicates the duration of VHH passive treatment. Graphics on the right side of the panel display humoral immune responses against RVA. Anti-RVA IgA in intestinal samples and serum IgG Ab titers were determined by ELISA at PIDs 0, 8 and 40. The # and * symbols indicate that the Ab titers of intestinal IgA and serum IgG, respectively, were significantly lower than the corresponding Ab titers in the untreated control group (One-way ANOVA). PID: Post Inoculation day.