(A – B) Flagellin (Flg) or PBS (Ctrl) was administered intravenously to mixed bone marrow (BM) chimeric mice reconstituted with equal parts Tlr5−/− and Il23a−/− (gene name for IL-23p19) bone marrow cells, as indicated. Three hours after flagellin administration, lamina propria IL-22 messanger RNA (mRNA) expression was assessed by quantitative PCR (qPCR) (A) and the serum concentration of IL-22 was assessed by ELISA (B) (n = 3 – 4 mice per group).
(C – D) Irradiated mice were reconstituted with a 1:1 mixture of IL-23p19-deficient (Il23a−/−) BM cells and CD11c.DTR BM cells to generate mixed BM chimeric mice, which were subsequently depleted of IL-23p19-sufficient dendritic cells by treatment with diphtheria toxin as described in Methods. Three hours after flagellin administration, lamina propria IL-22 mRNA expression was assessed by qPCR (C) and the serum concentration of IL-22 was assessed by ELISA (D) (n = 3 – 4 mice per group). Error bars denote ± s.e.m. Data are representative of two independent experiments.