Figure 3.

IRF4 drives a pro-inflammatory, Th17 cell differentiation promoting and putatively presence of functional Th17 cells increasing molecular gene expression signature in colitis tissues in a T cell-extrinsic manner. Rag1 ^−/− and Rag1 ^{− / −} Irf4 ^−/− mice were injected i.p. with 1 × 10⁶ naïve (CD4⁺CD25⁻) T cells. When colitis was established in Rag1 ^−/− mice five to six weeks after T cell transfer, both Rag1 ^−/− and Rag1 ^{− / −} Irf4 ^−/− mice were sacrificed. Gene expression levels of (A) Ifng, Il17a, Csf2, Tnf, (B) Il12a, Il1b, Il6, Il23a, Il23r, (C) Tbx21, Rorc, and Batf transcripts within colonic tissue were analyzed and quantitated by qPCR. Mean of gene expression levels detected in colonic tissues of Rag1 ^−/− mice was arbitrarily set down to 1, and all other gene expression levels were normalized to the expression level detected within Rag1 ^−/− mice. Data are combined from three individual experiments (Rag1 ^−/− n = 13; Rag1 ^{− / −} Irf4 ^−/− n = 13). Data were analyzed by Student’s t test and are shown as mean ± SEM. ns, not significant. *p < 0.05.