Identification ofAcvr2aas a Th17 Cell-Specific Gene Induced during Th17 Differentiation

IL-17-producing T lymphocytes have been found to comprise a distinct lineage of T helper cells (Th17 cells) that are major causes of autoimmune diseases such as EAE, RA, and IBD. In this study, we found that activin receptor type-2A (Acvr2a) is a gene induced during the differentiation of this effector cell lineage as compared with naïve T cells. The transcript of Acvr2a was not induced in Th1 and Th2 cells, and both TGF-β and IL-6 were required for the induction of Acvr2a. When the differentiation of Th17 cells was inhibited by all tarans retinoic acid (ATRA) which induces regulatory T cell (Treg) differentiation under Th17 differentiation conditions, expression of Acvr2a was also inhibited. Hence we propose that Acvr2a is a Th17 specific gene making Th17 cells distinct from other helper T cells, Th1, Th2, and Treg.