An IL-4-independent and CD25-mediated function of c-maf in promoting the production of Th2 cytokines.

c-maf is a T helper (Th)2 cell-specific transcription factor, which promotes the differentiation of Th2 cells mainly by an IL-4-dependent mechanism. It remains unclear whether c-maf possesses any IL-4-independent function in regulating the production of Th2 cytokines. Here, we provide evidence demonstrating that c-maf, independent of IL-4, is essential for normal induction of CD25 in developing Th2 cells. The levels of CD25 are significantly higher in developing Th2 cells than in developing Th1 cells during in vitro differentiation. In addition, timely blockade of IL-2 receptor signaling selectively inhibits the production of Th2 cytokines, but not IFN-gamma or IL-2. Taken together, our results uncover an IL-4-independent and CD25-mediated function of c-maf in promoting the production of Th2 cytokines.