Figure 3.

IL-23 Directly Promotes Intestinal T cell Proliferation

(A and B) C57BL.6.Rag1^−/− mice were transferred with 4 × 10⁶ CFSE-labeled CD4⁺CD45RB^hi T cells from WT or Il23r^−/− donors and sacrificed 12 days after transfer. (A) Total CD4⁺ T cell numbers and (B) representative flow cytometry plots showing CFSE dilution profiles of T cells from the spleen and colon are presented.

(C–E) C57BL.6.Rag1^−/− mice were transferred with 4 × 10⁵ CD4⁺CD45RB^hi T cells from WT or Il23r^−/− donors and sacrificed when recipients of WT T cells developed clinical signs of disease (∼6 weeks after transfer). IL-17A, IFN-γ, and Ki67 expression in CD4⁺ T cells from the colon were assessed by intracellular flow cytometry after in vitro restimulation with PMA and ionomycin. (C) Frequencies, (D) representative flow cytometric plots (numbers in gate represent frequencies), and (E) total numbers of IL-17A⁺IFN-γ⁻Ki-67⁺, IL-17A⁺IFN-γ⁺Ki-67⁺, and IL-17A⁻IFN-γ⁺Ki-67⁺ CD4⁺ T cells in the colon. Data represent pooled results from two independent experiments (A and B) or of a single experiment (C–E), bars represent the mean, error bars represent the SEM, and each symbol represents an individual mouse. Statistical significance was determined with the Mann-Whitney test, n = 4-11 (WT), n = 5-11 (Il23r^−/−).