IL21, Human, HEK293 Cells,Tag Free

Interleukin-21 (IL-21) is a potent cytokine regulating many cell types of the immune system. IL-21 is produced by activated T follicular helper cells (Tfh), Th17 cells, and NKT cells (2-7). Tfh-derived IL-21 plays an important role in the development of humoral immunity through its autocrine effects on the Tfh

cell and paracrine effects on immunoglobulin affinity maturation, plasma cell differentiation, and B cell memory responses (4, 8, 9). IL-21 protein regulates

several aspects of T cell function. It co-stimulates the activation, proliferation, and survival of CD8+ T cells and NKT cells and promotes Th17 cell polarization (

3, 5, 6, 10, 11). IL-21 blocks the generation of regulatory T cells and their suppressive effects on CD4+ T cells (12, 13). In addition to its role in T cell biology, IL-21 also plays a critical role in B cell activation, proliferation, differentiation, and apoptosis (2). IL-21 protein exerts its biological effects through a

heterodimeric receptor complex of gamma c and the IL-21-specific IL-21 R (2, 7). IL-21 is an approximately 14 kDa four-helix-bundle member of the family ofcytokines that utilize the common gamma chain (gamma c) as a receptor subunit. gamma c is also a subunit of the receptors for IL-2, IL-4, IL-7, IL-9, and IL

-15 (1). IL-21 R engagement enhances the cytolytic activity and IFN-gamma production of activated NK cells but limits the expansion of resting NK cells

(14). Dysregulation of the IL-21/IL-21 R system contributes to the development of multiple immunological disorders (1, 15). The 133 amino acid (aa) mature human IL-21 protein shares 63% and 61% aa sequence identity with mouse and rat IL-21 protein, respectively. Alternative splicing generates an additional

isoform with a substitution of the C-terminal 16 amino acids (16, 17).

1. Tangye, S.G. (2015) Curr. Opin. Immunol. 34:107.

2. Parrish-Novak, et al. (2000) Nature 408:57.

3. Coquet, J.M. et al. (2007) J. Immunol. 178:2827.

4. Vogelzang, A. et al. (2008) Immunity 29:127.

5. Korn, T. et al. (2007) Nature 448:484.

6. Nurieva, R. et al. (2007) Nature 448:480.

7. Asao, H. et al. (2001) J. Immunol. 167:1.

8. Zotos, D. et al. (2010) J. Exp. Med. 207:365.

9. Rankin, A.L. et al. (2011) J. Immunol. 186:667.

10. Frohlich, A. et al. (2009) Science 324:1576.

11. Yi, J.S. et al. (2009) Science 324:1572.

12. Peluso, I. et al. (2007) J. Immunol. 178:732.

13. Bucher, C. et al. (2009) Blood 114:5375.

14. Kasaian, M.T. et al. (2002) Immunity 16:559.

15. Tamagawa-Mineoka, R. et al. (2011) J. Invest. Dermatol. 131:1513.

16. Ma, J. et al. (2011) Cytokine 56:133.

17. Rahman, M. et al. (2007) FEBS Lett. 581:4001.