Figure 5. The IL-2 induced phosphorylation of STAT5 is impaired in c-rel^−/− nTreg precursors.

Purified nTreg precursors and nTregs isolated from foxp3^gfp and c-rel^−/−foxp3^gfp mice stimulated with IL-2, IL-7 or IL-2 plus IL-7 for 30 minutes, were fixed, permeabilized and stained with antibodies to phospho-STAT5. (A) Phospho-STAT5 levels in cytokine stimulated wt and c-rel^−/− nTreg precursors (CD25⁺Foxp3⁻CD4SP thymocytes). Histograms show expression levels (mfi) of phospho-STAT5 in wt (solid line) and c-rel^−/− (broken line) nTreg precursors without (black lines) or in response to cytokine stimulation (red lines). (B) Phospho-STAT5 levels in IL-2 stimulated wt and c-rel^−/− nTregs (CD25⁺Foxp3⁺CD4SP thymocytes). (C) Percentages of CD25^hiFoxp3⁺ cells developing in cultures of wt and c-rel^−/− nTreg precursors (CD25⁺Foxp3⁻CD4SP cells) co-stimulated with IL-2 plus IL-7. Experiments were performed as described in Fig. 3. The data shown in A and B are representative of three independent experiments, using 3 mice of either genotype in each experiment, while the data shown in panel C is based on three independent experiments.