recombinant human interleukin 21

Recombinant human interleukin 21 (rIL-21 or rHu IL-21) is a biologically active cytokine analog of the naturally occurring human interleukin 21. It is a single-chain, non-glycosylated protein consisting of 132 amino acids and typically produced in E. coli expression systems[2][5][8]. As a class I cytokine, it mediates immune activation by binding to the interleukin 21 receptor (IL-21R) on various immune cells. This interaction leads to dimerization with the common gamma chain (γc), activating Janus kinase 1 and Janus kinase 3 (JAK1/JAK3), which subsequently phosphorylate and activate STAT3 as well as STAT1 and STAT5 to a lesser extent[6]. The downstream effects include enhanced proliferation and cytotoxic activity of CD8+ T cells and natural killer (NK) cells, increased production of interferon-gamma (IFNγ), perforin, granzyme B, and other molecules associated with antitumor immunity[1][6]. Recombinant human IL-21 has been investigated primarily for its immunomodulatory properties in cancer therapy—especially metastatic melanoma and renal cell carcinoma—where it has shown biological activity with an acceptable safety profile in early-phase clinical trials[1][4].

Other names

recombinant human IL-21rhIL-21rhIL21rhIL 21IL-21IL21IL 21