Fig. 6

Apyrase enhances the induction of IgA by inactivated oral vaccines. SPF and GF mice were untreated (CTRL) or immunized with PA-S.Tm transformants together with crudely-purified apyrase (APY extract) or mock extract (mock extract) where indicated, pretreated with streptomycin, infected with S.Tm^WT (10⁸ CFU i.g.) and analysed 24 h later. a Intestinal lavage IgA titer and b pathogen loads (CFU) in mLN, liver and spleen in SPF mice either non-immunized (CTRL) or immunized with PA-S.Tm^pBAD28 or PA-S.Tm^pApyr. c Representative H&E sections of the cecum from SPF mice at 24 h post infection and statistical analysis of histopathological scores. Star: submucosal edema; white arrow: neutrophils aggregates; black arrow: epithelial defects; arrowhead: goblet cells. Scale bar: 50 µm. d Intestinal anti-S.Tm IgA titer, e pathogen loads (CFU) in mLN, liver and spleen and f statistical analysis of histopathological scores in non-immunized mice (CTRL) and mice immunized with PA-S.Tm^pBAD28 conditioned with the indicated extract. g Intestinal lavage IgA titer and h pathogen loads (CFU) in mLN, liver and spleen in GF mice either non-immunized (CTRL) or immunized with PA-S.Tm^pBAD28 or PA-S.Tm^pApyr. The boxplots show median and upper and lower quartiles. The extreme lines show the highest and lowest value . The boxplot is overlaid with the visualization of single observations. Kruskal–Wallis with Dunn’s post-test. *p < 0.05, **p < 0.01, ***p < 0.001. One representative experiment out of two is shown