IL17A and inflammatory bowel disease: To further understand how the increased IL-17 production by the CD5lo subset is associated with its ability to induce rapid and robust IBD, we administered BrdU via drinking water (to measure proliferative activity) or orally administered FITC-conjugated dextran (to measure gut epithelial leakage) to Rag1−/− mice adoptively transferred with CD5lo, Ly6C−, and Ly6C+ subsets 48 or 4 h prior to analysis on days 7 and 14 post-transfer (Supplementary Fig. 2k, l).