2007/10/22 by Rosanne Spolski, Warren J. Leonard · 1 citation
Immunology and Microbiology · #Acquired immune system #Autoimmunity #Biology #CD8 #Cell biology #Cytokine #Cytotoxic T cell #IL-2 receptor #Immune Cell Function and Interaction #Immune system #Immunology #Innate lymphoid cell #Interleukin #Interleukin 12 #Interleukin 15 #Interleukin 21 #NFAT #Natural killer T cell #Psoriasis: Treatment and Pathogenesis #T cell #T-cell and B-cell Immunology #Transcription factor #ZAP70
paper · doi:10.1146/annurev.immunol.26.021607.090316
openalex publication_date 2007/10/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/15
Interleukin-21 (IL-21), a potent immunomodulatory four-alpha-helical-bundle type I cytokine, is produced by NKT and CD4(+) T cells and has pleiotropic effects on both innate and adaptive immune responses. These actions include positive effects such as enhanced proliferation of lymphoid cells, increased cytotoxicity of CD8(+) T cells and natural killer (NK) cells, and differentiation of B cells into plasma cells. Conversely, IL-21 also has direct inhibitory effects on the antigen-presenting function of dendritic cells and can be proapoptotic for B cells and NK cells. IL-21 is also produced by Th17 cells and is a critical regulator of Th17 development. The regulatory activity of IL-21 is modulated by the differentiation state of its target cells as well as by other cytokines or costimulatory molecules. IL-21 has potent antitumor activity but is also associated with the development of autoimmune disease. IL-21 transcription is dependent on a calcium signal and NFAT sites, and IL-21 requires Stat3 for its signaling. The key to harnessing the power of IL-21 will depend on better understanding its range of biological actions, its mechanism of action, and the molecular basis of regulation of expression of IL-21 and its receptor.