IL21 (interleukin 21) is a member of the γ-chain type I cytokine family, and a four-α-helix bundle pleiotropic cytokine. This gene is localized to human chromosome 4q26–q27. Although, it is predominantly produced by T follicular helper (TFH) and T helper-17 (TH17) cells, it is also produced by CD4+ T cells, neutrophils and natural killer cells. Under certain conditions, it is also produced by CD8+ T cells. Recombinant human IL-21 is a 15.0 kDa protein consisting of 132 amino acid residues.
IL21 (interleukin 21) functions on its heterodimeric receptor IL21R, which is expressed widely on immune and non-immune cells. Therefore, IL21 exerts its effects on a wide range of cell types and has a pleiotropic role in immune response regulation. This protein activates Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway and functions through mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)-AKT signaling pathways. Studies show that in rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), IL21 facilitates migration, invasion and production of MMPs (MMP-2, MMP-3, MMP-9, MMP-13) (matrix metalloproteinases). Therefore, it has potential as a therapeutic target in the treatment of RA. Studies show that CD3+TCRvβ11+ NK (natural killer) T cells isolated from a local Mycobacterium tuberculosis infection site produce IL21, which in turn assists B cells to produce and release IgG (immunoglobulin) and IgA, to help fight the infection.
MQDRHMIRMR QLIDIVDQLK NYVNDLVPEF LPAPEDVETN CEWSAFSCFQ KAQLKSANTG NNERIINVSI KKLKRKPPST NAGRRQKHRL TCPSCDSYEK KPPKEFLERF KSLLQKMIHQ HLSSRTHGSE DS
Lyophilized from a sterile (0.2 micron) filtered aqueous solution containing 10 mM sodium phosphate, pH 7.5
Centrifuge the vial prior to opening. Reconstitute in water to a concentration of 0.1-1.0 mg/ml. Do not vortex. This solution can be stored at 2-8°C for up to 1 week. For extended storage, it is recommended to further dilute in a buffer containing a carrier protein (example 0.1% BSA) and store in working aliquots at -20°C to -80°C.