title: Interleukin 21: a cytokine/cytokine receptor system that has come of age.
abstract: Interleukin-21 (IL-21) and its receptor represent the sixth cytokine system whose actions were recognized to require the common cytokine receptor gamma chain. IL-21 is produced by activated CD4+ T cells, natural killer T cells, and follicular T helper cells and has actions on a range of lymphohematopoietic lineages. Among its many effects, IL-21 serves a critical role for immunoglobulin production and terminal B cell differentiation, acts as a T cell comitogen and can drive the expansion of CD8+ T cells, can negatively regulate dendritic cell function and plays an essential role in the differentiation of Th17 cells. Importantly, IL-21 is implicated in the pathogenesis of autoimmunity and exhibits potent actions as an antitumor agent. The ability to regulate and manipulate the actions of IL-21, therefore, has important implications for immunoregulation and the therapy of human disease.
authors.affiliation: Laboratory of Molecular Immunology, National Heart, Lung, and Blood Institute, Bldg. 10, Rm. 7B05, Bethesda, MD 20892-1674, USA. wil@helix.nih.gov
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Leonard
authors.forename: Rong
authors.initials: R
authors.lastname: Zeng
authors.forename: Rosanne
authors.initials: R
authors.lastname: Spolski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015551:Autoimmunity; D016207:Cytokines / Q000502:physiology*; D003713:Dendritic Cells / Q000276:immunology / Q000502:physiology; D004847:Epithelial Cells / Q000502:physiology; D006801:Humans; D007378:Interleukins / Q000502:physiology*; D015603:Keratinocytes / Q000502:physiology; D018121:Receptors, Cytokine / Q000502:physiology*; D053655:Receptors, Interleukin-21 / Q000502:physiology*; D018418:Th2 Cells / Q000276:immunology / Q000502:physiology; D000098546:Interleukin-21
chemical_list: D016207:Cytokines; D007378:Interleukins; D018121:Receptors, Cytokine; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21