CXCR6-EGFP/+ mice27 are susceptible to DSS-induced colitis (Supplementary Fig. 1) and can be used to track intestinal CD4+ T cell subsets, including the relatively rare iNKT cells (Supplementary Fig. 2), under homeostatic conditions26 and during experimental intestinal inflammation. This evidence concerns the gene CXCR6 and colitis.