Fig. 7: Downregulation of Ccr9 in CD4⁺ T cells preferentially develops CD4⁺CD8αα⁺ IELs in a Cbfb-dependent manner.

a Schema of the experimental design. Naive CD4⁺ T cells obtained from Ccr9^+/+ and Ccr9^−/− mice were nucleofected with siRNA targeting negative control, Ccr9, Runx3, Cbfb, and Tbx21 (scramble, siCcr9, siRunx3, siCbfb, and siTbet, respectively). Nucleofected cells were cultured with anti-CD3/CD28, transforming growth factor-β (TGF-β), retinoic acid (RA), 2,3,7,8-tetrachlododibenzodioxin (TCDD), and IFN-ɤ. Surface CD8α and intracellular Foxp3 expression were analyzed 3 days after culture. b, c Graphs show the frequency of CD8α⁺ cells among TCRβ⁺CD4⁺CD8β^– nucleofected naive CD4⁺ T cells obtained from Ccr9^+/+ and Ccr9^−/− mice cultured with anti-CD3/CD28, TGF-β, RA, TCDD, and IFN-γ. Three independent experiments were performed in triplicate. Each dot (n = 3) represents the mean of the triplicate. Data are expressed as mean ± SD. One-way ANOVA with Tukey’s multiple comparisons post hoc test was applied. Source data are provided as a Source data file.