Fig 4. Effect of pre-symptomatic therapeutic administration of VHH on RVA-induced diarrhea and host humoral immune response against RVA.

All mice were orally inoculated with ECw RVA (1778 DD₅₀) 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 panel depict intestinal infectious RVA titer and the incidence of diarrhea. 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 purple line indicates the duration of VHH passive treatment. Graphics on the right side of the panel display mice humoral immune response against RVA. Anti-RVA IgA in intestinal samples and serum IgG Ab titers were determined by ELISA at PID 0, 8 and 40. The # and * symbols indicate that Ab titers of intestinal IgA and serum IgG were significantly lower than Ab titers in the untreated control group (One-way ANOVA). PID: Post Inoculation Day.