Abstract
Interleukin (IL)-21 is a cytokine that affects the differentiation and function of lymphoid and myeloid cells and regulates both innate and adaptive immune responses. In addition to regulating the immune response to tumor and viral infections, IL-21 also has a profound effect on the development of autoimmune and inflammatory diseases. IL-21 is produced mainly from CD4+ T cells—in particular, follicular helper T (Tfh) cells—which have a great influence on the regulation of antibody production. It is also an important cytokine for the activation of CD8+ T cells, and its role in recovering the function of CD8+ T cells exhausted by chronic microbial infections and cancer has been clarified. Thus, IL-21 plays an extremely important role in viral infections, especially chronic viral infections. In this review, I will introduce the findings to date on how IL-21 is involved in some typical viral infections and the potential of treating viral diseases with IL-21.
Highlights
IL-21 is a major cytokine produced by Tfh cells along with IL-4 and CXCL13, and IL-21, IL-4 and CD40L are major stimulators for the regulation of antibody production by T-cell-dependent activated B cells in the germinal center [22]
IL-21 is a multifunctional cytokine that acts on various immune cells
IL-21 is a major cytokine produced by Tfh cells, and it has been clarified that it has an effect of promoting optimal antibody production on Bcells through class switch recombination and somatic hypermutation
Summary
Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. 10 years, immune checkpoint inhibition that inhibits for thetumors, PD-L1-PD-1 and exhausted T cells, andhas is actively used as the treatment method for tumors. That a treatment method combining an immune checkpoint inhibitor and IL-21 cytokine effector T cells and suppressing CD8 T cell exhaustion [42]. In the future, it is expected therapy will be developed as an approach to immunotherapy for chronic viral infections and tumors. That a treatment method combining an immune checkpoint inhibitor and IL-21 cytokine therapy will be developed as an approach to immunotherapy for chronic viral infections and tumors. IL-21 suppresses the exhaustion of CD8+ T cells to maintain the immune response against chronic viral infections. Regarding the mechanism by which IL-21 inhibits differentiation into exhausted T cells, Loschinski et al showed in an in vitro study that IL-21 induces fatty acid oxidation and oxidative phosphorylation in mitochondria to induce memory T cell differentiation and to inhibit exhausted T cell differentiation [48]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
