Pivotal Roles of T-Helper 17-Related Cytokines, IL-17, IL-22, and IL-23, in Inflammatory Diseases

Figure 1

Differentiation of naïve CD4⁺ T cells. Upon certain stimulating conditions, naïve CD4⁺ T cells differentiate into different subpopulations, such as Th1, Th2, Th17, and regulatory T cells (Tregs). Th1: T-helper 1 cell; Th2: T-helper 2 cell; Th17: T-helper 17 cell; IL: interleukin; TGF-β: transforming growth factor-β; IFN-γ: interferon-γ; TNF-α: tumor necrosis factor-α; GM-CSF: granulocyte macrophage colony-stimulating factor; DC: dendritic cell; RA: retinoic acid.