Interestingly, TGF-β1 plays a role in the induction from CD4+ T cells of both induced Tregs (iTregs), which have a regulatory function, and TH17 cells, which secrete pro-inflammatory cytokines [REF].
TGF-β1 alone precipitates the expression of Foxp3 and Treg differentiation from activated T helper cells, and the mechanism for this differentiation is unknown for both induced T regulatory cells as well as natural T regulatory cells.