Description: Mouse Interleukin-21 (IL-21) is a 146-amino acid protein with 57% identity to the human gene. It contains a 24-amino acid signal peptide and a 4-helix-bundle cytokine domain homologous to IL-2, IL-4 and IL-15. IL-21 stimulates B cell proliferation in an anti-CD40 dependent manner but inhibits B cell proliferation stimulated by IL-4 plus anti-IgM. IL-21 is induced by IL-6 in activated T cells, a process that is dependent on STAT3 but not on ROR-gamma. IL-21 induces Th17 differentiation and suppresses FOXP3 expression, which requires STAT3 and ROR-gamma.
