Figure 4.

Germinal centre reaction after oral administration of a RASV strain in vivo. Wild-type and IκBζ^−/− mice were orally immunised with 10⁹ CFU of a RASV strain per mouse twice at 2-week intervals. (A) Representative H&E image of the spleen from an unimmunized mouse, 14 d after the first RASV oral administration (D14) and 14 d after the second RASV oral administration (D28). (B) Splenic follicle size was measured from histologic images. (C) Fourteen days after the second oral immunisation with RASV, the total IgG Ab level was measured in the serum. Data are representative of three independent experiments. ns, not significant; ^*P < 0.05 and ^***P < 0.001 based on ANOVA with Bonferroni’s multiple comparison test.