FIG 3.

C. rodentium-induced CD4⁺ T_RM cells exhibit a T_h1 and T_h17 profile. (A) Mucosal CD4⁺ CD44⁺ CD69⁺ T cells exhibit a T_h17 and T_h1/17 signature over the long term after C. rodentium infection. Mucosal CD4⁺ CD44⁺ CD69⁺ T cells isolated from the colon of C. rodentium-infected mice at the indicated time points were stimulated with phorbol myristate acetate and ionomycin, and expression of IL-17A and of IFN-γ was determined. m, months. (B) Data from panel A are quantified and presented as IL-17A and IFN-γ single-positive (top left and right panels, respectively) and double-positive (bottom panel) CD4⁺ T_RM cells. (C and D) Increasing fractions of IL-17A- (C) and IFN-γ-producing (D) CD4⁺ T cells express T_RM markers after C. rodentium infection. Expression of CD44 and CD69 on IL-17A⁺ (C) and IFN-γ⁺ (D) mucosal CD4⁺ T cells from C. rodentium-infected mice was determined at baseline (0) and 6 months (6 m) relative to uninfected 6-week-old mice or relative to uninfected age-matched controls (D, bottom panel). The following gating schema was used: live lymphocytes→IL-17A⁺ (or IFN-γ⁺)→CD3⁺→CD4⁺→CD44 versus CD69. FACS plots (left panels) and quantitated data (right panels and bottom panel of panel D) are presented. (E and F) C. rodentium-induced CD4⁺ T_RM cells produce IL-17 and IFN-γ independently of CD103 expression. Coordinated expression of CD103 and IL-17A (E) or CD103 and IFN-γ (F) was determined in CD4⁺ CD44⁺ CD69⁺ mucosal T cells at the indicated time points postinfection and quantified (right panels). Panel A is a representative plot, while 6 to 9 mice (B and C) or 6 to 11 mice (E and F) are presented for each time point. *, P < 0.5; **, P ≤ 0.01; ***, P ≤ 0.001; ****, P < 0.0001, by ANOVA.