a, Wild-type mice were given 1-MIM-OH or carrier control (ctrl) by gavage. Quantification of DNA adducts at the indicated time points (control 4 h, n = 2; control 8 h, n = 4; control 24 h, n = 2; 1-MIM-OH 4 h, n = 4; 1-MIM-OH 8 h, n = 8; 1-MIM-OH 24 h, n = 6; mean ± s.e.m.). b, Schematic representation of the different treatment regimens. c–g, Mice of the indicated genotypes were exposed to 1-MIM-OH (c, f) or I3C (d, e, g) by gavage and analysed 8 h later. c, d, Representative flow cytometry analysis of IL-22 production by the indicated lymphocyte populations after gavage with 1-MIM-OH (c) or I3C (d). CD4+ T cells were defined as CD45+ lineage marker (Lin)+CD4+ cells, ILC3 as CD45+Lin−RORγt+ cells, and γδ T cells as CD45+Lin+γδTCR+ cells. Numbers indicate percentage of cells in gate. e, Representative flow cytometry analysis and quantification of IL-22 and IL-10 production by Lin+CD4+FOXP3+ Treg cells 8 h after gavage with I3C (control, n = 4; I3C, n = 4; mean ± s.e.m.). f, g, Expression of the IL-22 response gene Reg3g in primary colon epithelial cells was determined by qRT–PCR 8 h after gavage with 1-MIM-OH (f; Il22+/+ control, n = 5; Il22+/+ 1-MIM-OH, n = 4; Il22−/− control, n = 3; Il22−/− 1-MIM-OH, n = 6; mean ± s.e.m.) or I3C (g; n = 5; mean ± s.e.m.). h, Percentage of IL-22+ cells among the indicated lymphocyte subsets 8 h after 1-MIM-OH treatment of Ahr−/− mice (control, n = 3; 1-MIM-OH, n = 4; mean ± s.e.m.). i, Numbers of IL-22+ ILC3 cells at different time points after 1-MIM-OH gavage (control, n = 2; 1-MIM-OH, n = 4; 1-MIM-OH 24 h, n = 6; mean ± s.e.m.). Data are representative of two biologically independent experiments.