Cytokines for polarizing human T cells into Th9 cells. Th9 cells are a unique subset of T helper cells that produce IL-9. An important function of IL-9 producing T cells is fighting inflammation and helminth infections. Th9 cells can be generated from naive CD4+ T cells in culture by culturing them in the presence of IL-4 and TGF-β 1. It also appears that IFNγ and IL-27 can inhibit the generation of Th9 cells.