Description: The mouse IL-21 ELISA is an enzyme-linked immunosorbent assay for the quantitative detection of mouse IL-21. The mouse IL-21 ELISA is for research use only. Not for diagnostic or therapeutic procedures.
IL-21 is a 17 kDa immunomodulatory cytokine produced mainly by NKT, Th17 and T follicular helper (TFH) cells. In TFH cells, IL-21 expression leads to autocrine signaling through the IL-21 receptor (IL-21R) and STAT3, which leads to additional transcriptional activation by Bcl6. This cytokine plays a role in T cell-dependent B cell differentiation into plasma cells and memory cells, stimulation of IgG production and induction of apoptotic signaling in naive B cells. In Th17 cells, IL-21 expression and autocrine feedback through STAT3, IRF4 and ROR gamma (t) lead to upregulation of the IL-23R, thereby preparing Th17 cells for maturation and maintenance by the inflammatory cytokine IL-23. While upregulating IRF4 and ROR gamma (t), IL-21 also mediates the downregulation of Foxp3. High levels of IL-21 are present in chemically induced colitis models. IL-21-deficient mice are protected from developing colitis upon chemical treatment by their inability to upregulate Th17-associated molecules.