Figure 1
Cytokines regulate immune tolerance by affecting T cell activation and differentiation. Transforming growth factor (TGF)- β1, interleukin (IL)-10, and IL-27 inhibit the antigen presentation of antigen presenting cells (APCs) and alter the subsequent activation and differentiation of T helper (Th) cells. IL-2 is a tolerogenic cytokine that controls the generation and survival of regulatory T cells (Tregs). IL-21 serves as an autocrine cytokine in Th17 and follicular helper T cell (TFH) cell differentiation. IL-12 initiates Th1 cell differentiation, whereas IL-23 maintains Th17 cell differentiation. These cytokines are either required for maintaining self-immune tolerance or involved in autoimmune pathology.