Fig. 2: NOD2 deficiency increases IgA retrograde transport in mice.

a Tissue section showing a PP obtained from a ligated intestinal loop in WT, NOD2 KO or WT mice after MDP-PAM stimulation following exposure to SIgA-Cy3 for 60 min. Mouse IgG and the BSA were used as negative controls. The graph shows the number of SIgA-positive cells per PP. This experiment was repeated on 6 mice per group and an average of 3 PP per mouse was done. Vertical bars show the mean value±SEM. One-way ANOVA followed by Bonferroni post hoc test was used (p values: *p < 0.05; ***p < 0.005). b Fecal bacteria from WT or Nod2KO mice were stained with anti-IgA-FITC and the MFI were calculated on IgA-bacteria. This experiment was repeated on 4 mice per group. Vertical bars show the mean value ± SEM. A nonparametric Mann–Whitney U-test was used (ns: not significant). c Lysed bacteria were used as the target antigens in a western blot, using serum (S) or fecal (F) supernatant from WT or NOD2 KO mice as primary antibody and anti–IgA-HRP as the secondary antibody. This experiment was repeated on eight cohoused mice (WT (n = 4), NOD2 KO (n = 4)) with similar results. NOD2 KO and littermate WT mice were cohoused and immunized orally with p24-SIgA. d Levels of Ag-specific mucosal IgA and e levels of serum IgG in littermate WT or NOD2 KO mice were shown. Vertical bars show the mean value ± SEM. n = 5 biologically independent mice per group. One-way ANOVA followed by Bonferroni post hoc test was used (p values: *p < 0.05; **p < 0.01). f Cytokine concentrations in serum and faeces were determined in triplicate by Luminex-multiplex cytokine assay in littermate WT (n = 3) and NOD 2 KO mice (n = 3). Cytokine profiles are shown as radar charts; each axis displays the mean quantity (pg/ml) of each cytokine after immunization with p24-SIgA, p24 and PBS. A nonparametric Mann–Whitney U-test was used. P values have been calculated by comparing the p24-SIgA group with the p24 group; *p < 0.05. Source data are provided as a Source Data file.