Fig. 6

Exogenous IL-25 induces type 2 immunity, as well as IL-13-dependent alterations in ileal AMP expression and SFB abundance. WT (a–c) or IL-13^−/− (d–f) mice were injected with IL-25 (i.p., 1 μg per mouse) daily for 3 days and euthanized at day 4. qPCR was carried out to examine expression of antimicrobial peptides (a, d), SFB-specific and universal bacterial 16S rRNA (b, e), and Th17-associated genes (c, f) in the ileum. The abundance of SFB is relative to vehicle after normalization to universal bacterial 16 s rRNA. The fold change is relative to vehicle after normalization to 18S rRNA. Data shown in bar graphs are the mean ± s.e.m. Mann–Whitney test (b, e) or two-tailed Student’s t-test (a, c, d, f) was used for comparisons between the two groups. *P < 0.05, **P < 0.01, ***P < 0.001 versus respective vehicle (n = 7 for BSA groups and WT-IL-25, n = 6 for IL-13^−/−-IL-25)