Figure 3. ETBF-mediated colon tumorigenesis is IL-17-dependent in Th17^null Min-CD4^Stat3-/- mice.

a, Il17a expression in tumor compared to normal colon tissue of parental Min (CD4^Stat3+/+) and Min-CD4^Stat3-/- (CD4^Stat3-/-) mice 3 months after ETBF colonization. The plot shows 2^-ΔΔCt where ΔΔC_t represents ΔCt_tum-ΔCt_norm . Each symbol represents one mouse. Mean +/- SEM. p values, non-parametric Mann Whitney U t test. b, Gene expression profile in CD4⁺ cells sorted from pooled distal colon tumors (3 to 5 tumors) in parental (CD4^Stat3+/+) and CD4^Stat3-/- (CD4^Stat3-/-) Min mice 3 months after ETBF colonization. RQ (CD4^Stat3+/+ / CD4^Stat3-/-) = 2^-ΔΔCt where ΔCt of genes of interest in ETBF Min-CD4^Stat3+/+ is compared to ETBF Min-CD4^Stat3-/-. Genes overexpressed in parental Min-CD4^Stat3+/+ mouse (RQ>2) and genes overexpressed in Min-CD4^Stat3-/- mouse (RQ<0.5) are indicated. The mean of expression from two independent experiments is shown. c, Representative flow cytometry analysis of enzymatically digested tumor tissue obtained from Min (CD4^Stat3+/+ , upper panels) and Min-CD4^Stat3-/- (CD4^Stat3-/-, lower panels) tumors 3 month after ETBF colonization. d, ETBF-colonized Min-CD4^Stat3-/- were treated with a blocking anti-IL-17 or isotype control Rat IgG1 mAbs twice weekly between week 6 and 12 following ETBF colonization. Mice were sacrificed 12 weeks after colonization and tumors were counted. Each symbol represents one mouse. Mean +/- SEM. p values, non-parametric Mann Whitney U t test.