Figure 9. Ras/MAPK activity is required for Tr1 cell development and IRF4 expression.

(a,b) WT naive IL-10^GFP/Foxp3^RFP reporter CD4⁺ cells were cultured under Tr1 differentiation conditions, in the presence or absence of ERK1/2 inhibitor (PD098059), JNK inhibitor (SP600125), p38 inhibitor (SB203580), or Ras inhibitor (Kobe0065). Viable CD4⁺ T cells were analyzed. (a) Representative FACS plots of IL-10^GFP/Foxp3^RFP, CD69/CD25 and IRF4 expression, and (b) summary of percentage of IL-10⁺Foxp3⁻ and CD25⁺CD69⁺ cells over viable CD4⁺ T cells, and relative IRF4 MFI (naive cell level set as 1). n=6. Data represent results of two experiments. *P≤0.05, **P≤0.01, ***P≤0.001, by one-way ANOVA with Tukey’s post-hoc test. Data presented as mean±s.e.m.