Figure 4.

An overview of the cytokines involved CD4+ T helper cell expansion and polarization. Naïve CD4+ T cells can differentiate into one of three lineages of effector T helper (Th) cells - Th1, Th2, and Th17 - following signaling via the T cell receptor and co-stimulatory receptors. The effector Th cell populations are defined based upon their cytokine production profile and perform distinct immunoregulatory functions. Th1 cells assist in regulating antigen presentation and cell-mediated immunity. Anti-parasite and humoral immunity is regulated by the cytokines produced by Th2 effector cells. The cytokines produced by the Th17 subset regulate an inflammatory response.