Cytokines for polarizing mouse T cells into Th9 cells. Th9 cells are a unique subset of T helper cells that produce IL-9. Although the exact function of IL-9 producing T cells is yet to be completely clear it is proposed that these cells could be important in 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-ß 1. It also appears that IFN? and IL-27 can inhibit the generation of Th9 cells.