Fig. 2

Induction of humoral immune response post-immunization. a, b The kinetics of appearance of IgG after immunization with Pd or Pd + FlaB given through intranasal (i.n.) and sublingual (s.l.) routes respectively. c The comparative serum-IgG antibody titers after final vaccination. d, e The kinetics of appearance of serum IgA antibodies after i.n. and s.l. inoculations of various antigens. The legends for (a), (b), (d), (e) are in (g). f The serum-IgA levels 1 week after final immunization. g The kinetics of appearance of feces-IgA after s.l. immunization. (h) The final feces-IgA titers 1 week after final vaccination. i–k The respective serum IgG, serum IgA and fecal IgA antibody titers from TLR5 ^−/− mice. Statistical differences were compared by the Student’s t test for unpaired means. *P < 0.05, **P < 0.01, ***P < 0.001, ^nsnot significant. The error bars represent the standard error of mean (SEM)