Fig. 4: Characterization of SI IEL T cells in CCR9^Tg mice.

a Frequencies and numbers of total CD4⁺ T cells among SI IEL T cells of WT and CCR9^Tg mice. Histograms are representative, and graphs show summary of 7 independent experiments with a total of 10 WT and 7 CCR9^Tg mice. b CD4^–CD8α⁺ SI IEL T cell numbers of WT and CCR9^Tg mice. Data show summary of 7 independent experiments with 10 WT and 7 CCR9^Tg mice. c Frequencies and numbers of CD8αβ and CD8αα IEL T cells in the SI from WT and CCR9^Tg mice. Contour plots show CD8α versus CD8β expression on CD8α⁺ IEL T cells, while the bar graphs show the summary of CD8αβ and CD8αα IEL T cell numbers. Data show summary of 7 independent experiments with a total of 10 WT and 7 CCR9^Tg mice. d Schematic of naive CD4 T cell adoptive transfer into Rag2^–/– lymphopenic host mice (top). The purity of donor CD4 T cells was confirmed by flow cytometry (middle). Frequency of CD4⁺CD8α^– and CD4⁺CD8αα⁺ DP cells among CD45.2⁺ donor CD4⁺CD8β^– T cells in the SI, large intestine (LI), mLN, and spleen of host mice was assessed after 6-8 weeks of adoptive transfer. Data are representative from 3 independent experiments. e Frequencies of IFNγ- (top) and TNFα-expressing (bottom) cells among CD4⁺CD8α^– (CD4SP) and CD4⁺CD8αα⁺ (DP) SI IEL T cells of WT mice. Contour plots are representative, and bar graphs show summary of 3 independent experiments with at least 4 WT mice. f Granzyme B (GzmB) expression in CD4SP and DP SI IEL T cells of WT mice. Histograms are representative (left), and bar graphs (right) show summary of 3 independent experiments with a total of 4 WT mice. g Runx3d-YFP reporter expression was assessed on CD4SP, DP and CD4^–CD8α⁺ (CD8SP) SI IEL T cells of Runx3d^YFP/+ reporter mice. Histograms are representative (left), and bar graph (right) shows summary of 3 independent experiments with a total of 4 Runx3d^YFP/+ reporter mice. Data are shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, n.s., not significant.