Fig. 1: Deletion of IκBζ in IECs causes an aberrant increase in Th17 cells in the small intestine and exacerbation of inflammatory diseases.

a A section of the jejunum was prepared from control (Nfkbiz^fl/fl) or IEC-specific IκBζ-deficient (Nfkbiz^fl/flVil1-Cre) mice and the expression of the indicated genes was analyzed by in situ hybridization. Magnified images of the yellow box are shown to the right. Scale bar, 50 μm. The villi are delineated by white lines. b, c The expression of Il17a (b) and Il17f (c) was determined by RT-qPCR. The mean expression levels are shown (n = 6 mice). d, e Lamina propria cells in the small intestine from the indicated mice were subjected to intracellular cytokine staining and analyzed by flow cytometry. The percentage of cells in each quadrant among FVD506^–CD45⁺CD4⁺TCR^β+ (CD4⁺ T) cells are shown (d). The results are representative of 7–8 independent experiments. The mean frequencies (percentages) of IL-17A⁺ cells among CD4⁺ T cells are shown (n = 7–8 mice per group) (e). f For induction of EAE, the indicated mice were immunized with MOG_31–55 peptide on day 0 and injected with Pertussis toxin on days 0 and 2. Clinical scores were determined every day, and the mean clinical scores ±SEM (n = 11 mice per group) are shown. Data are pooled results from two independent experiments. g For induction of enteritis in the small intestine, the indicated mice were intraperitoneally injected with an agonistic anti-CD3ε antibody (1.0 mg/kg) on days 0, 2, and 4, and the body weight was measured every 24 h. The body weight is given as the percentage relative to the value on day 0. Results are presented as mean ± SEM (n = 7–8 mice per group). Data are pooled results from two independent experiments. h For induction of colitis, the indicated mice were administered 2.0% DSS in drinking water for 5 days, followed by regular water without DSS in subsequent days. Body weight was measured every 24 h, and is shown as the percentage relative to the value on day 0. Results are presented as mean ± SEM (n = 12–13 mice per group). Data are pooled results from two independent experiments. Statistical significance was determined by the Mann–Whitney U test (b, c, e) or two-way ANOVA (f, g, h). *p < 0.05, **p < 0.01, n.s., not significant.