Tags: Protein.
Interleukin-21 also known as IL-21 is a protein that in humans is encoded by the IL21 gene.Interleukin-21 is a cytokine that has potent regulatory effects on cells of the immune system including natural killer (NK) cells and cytotoxic T cells that can destroy virally infected or cancerous cells. This cytokine induces cell division/proliferation in its target cells.