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Updated: Aug 20, 2026

Visualization of IL-22-expressing Lymphocytes Using Reporter Mice
Published on: January 25, 2017
Biology of IL-21 and the IL-21 receptor
Devangi S Mehta1, Andrea L Wurster, Michael J Grusby
1Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115, USA.
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.
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