IL17A and inflammatory bowel disease: Consistent with the enhanced IL-17A-producing ability, the Ccr6−/− CD5lo subset was able to induce a delayed (detectable at day 21), but the highest, onset of IBD symptoms (Fig. 3f, g), as well as the highest frequencies and numbers of IL-17A+ cells compared with those induced by the Ccr6−/− Ly6C− and Ly6C+ subsets (both in the LI and mLN; Fig. 3h and Supplementary Fig. 3k−n).