Cytokine with immunoregulatory activity. May promote the transition between innate and adaptive immunity. Induces the production of IgG(1) and IgG(3) in B-cells. May play a role in proliferation and maturation of natural killer (NK) cells in synergy with IL15. May regulate proliferation of mature B- and T-cells in response to activating stimuli. In synergy with IL15 and IL18 stimulates interferon gamma production in T-cells and NK cells (By similarity). During T-cell mediated immune response may inhibit dendritic cells (DC) activation and maturation. {ECO:0000250, ECO:0000269|PubMed:11970879, ECO:0000269|PubMed:12893770, ECO:0000269|PubMed:15100251}. Biological Activity: Fully biologically active when compared to standard. The ED50 as determined by a cell proliferation assay using human N1186 T cells is less than 25ng/ml, corresponding to a specific activity of > 4.0x10e4 IU/mg. Sequence: HKSSPQGPDR LLIRLRHLID IVEQLKIYEN DLDPELLSAP QDVKGHCEHA AFACFQKAKL KPSNPGNNKT FIIDLVAQLR RRLPARRGGK KQKHIAKCPS CDSYEKRTPK EFLERLKWLL QKMIHQHLS Molecular Weight: 15.0kD PubMed ID: 11081504, 11970879, 12893770, 15100251 Gene Name: Il21 Swiss Prot: Q9ES17 Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile PBS. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
