Regulation and Immune Function of IL-27.

IL-27 is a pleiotropic cytokine that has diverse immune regulatory activities under both physiological and pathological conditions. IL-27 enhances the functions of Th1 and CD8+ T cells, promotes the development of Tfh and Tr1, and suppresses the functions of Th2, Treg, Th9, and Th17 cells. IL-27 is also involved in regulation of immune responses of B cells, NK, DCs, and macrophages. IL-27 production is strictly regulated at both transcriptional and posttranscriptional levels. Given its broad effects on immune regulation, IL-27 has been implicated in the pathogeneses of autoimmune and infectious diseases as well as cancers. In this chapter, the biological characters of IL-27 have been reviewed, including the molecular mechanisms of IL-27 production and the underlying cellular signaling pathway. The regulatory effects of IL-27 on immune responses in autoimmune disease, infectious disease, and cancer are also discussed.