Fig 2: IL-2 rescues IRF4 expression in Itk-/- CD4 T cells.(a) Sorted naive CD4+ T cells differentiated for 3 days under Th9 plus TL1A in absence or presence of blocking anti-IL-2 plus hIL-2, were stained for IRF4 and analysed by flow cytometry. (b) mRNA of Irf4 and Maf in cells differentiated as in a evaluated by qRT-PCR. (c) Itk-deficient CD4+ T cells were transduced with constitutively active STAT5 (ca-STAT5) or control retroviruses, differentiated under Th9 plus TL1A conditions and intracellular IRF4 determined. (d) Sorted naive WT CD4+ T cells were differentiated under Th9 plus TL1A with 0.003 or 0.01 µg ml-1 of anti-CD3, in absence or presence of blocking anti-IL-2 or blocking anti-IL-2 plus hIL-2, then restimulated with PMA and Ionomycin and IL-9 and IRF4 production were analysed by intracellular staining, MFI values for IRF4 are indicated. Data in figures a-d are representative examples from one of at least three independent experiments.

Fig 3: IL-2 rescues pSTAT5 and pS6 in Itk-/- CD4 T cells.(a-c) Sorted naive CD4+ T cells from WT and Itk-/- mice were differentiated for 3 days under Th9 or Th9 plus TL1A conditions in absence or presence of blocking anti-IL-2 plus hIL-2 and analysed for pSTAT5 (MFI are indicated) (a) CD25 (b) and pS6 (c). (d) Itk-deficient CD4+ T cells were transduced with control (MIGR) or constitutively active STAT5-expressing retroviruses, differentiated under Th9 plus TL1A conditions and IL-9 production determined by intracellular staining after PMA and Ionomycin restimulation. Results in a-d are representative of one out of at least 3 experiments.