title: Biology of IL-21 and the IL-21 receptor.
abstract: Interleukin-21 (IL-21) is the newest member of the common gamma-chain family of cytokines, which includes IL-2, IL-4, IL-7, IL-9, IL-13, and IL-15. Its private receptor, IL-21R, has been shown to activate the Janus kinase/signal transducers and activators of transcription signaling pathway upon ligand binding. Initial studies have demonstrated that IL-21 has pleiotropic effects on the proliferation, differentiation, and effector functions of B, T, natural killer, and dendritic cells. More recently, the potential therapeutic capacity of IL-21 in the treatment of cancers has been widely investigated. The biological role of IL-21 in the immune system is complex, as IL-21 has been shown to have the ability to both promote and inhibit immune responses. Overall, the current data point to IL-21 being a novel immunomodulatory cytokine, whose regulation of any given immune response is highly dependent on the surrounding environmental context.
authors.affiliation: Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: Devangi S
authors.initials: DS
authors.lastname: Mehta
authors.forename: Andrea L
authors.initials: AL
authors.lastname: Wurster
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Grusby
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D003713:Dendritic Cells / Q000502:physiology; D006801:Humans; D053738:Interleukin-21 Receptor alpha Subunit; D007378:Interleukins / Q000235:genetics / Q000502:physiology*; D007694:Killer Cells, Natural / Q000502:physiology; D051379:Mice; D018123:Receptors, Interleukin / Q000235:genetics / Q000502:physiology*; D053655:Receptors, Interleukin-21; D015398:Signal Transduction / Q000502:physiology; D013601:T-Lymphocytes / Q000502:physiology; D000098546:Interleukin-21
chemical_list: C508117:IL21R protein, human; C508118:Il21r protein, mouse; D053738:Interleukin-21 Receptor alpha Subunit; D007378:Interleukins; D018123:Receptors, Interleukin; D053655:Receptors, Interleukin-21; D000098546:Interleukin-21