Invitrogen™ Human IL-33 ELISA Development Kit (ABTS), PeproTech®

IL-33 (Interleukin-33) is a 270 amino acid, highly divergent protein belonging to the IL-1 family with an IL-1-like C-terminal domain. IL-33 is a dual function protein that may function both as a proinflammatory cytokine and an intracellular nuclear factor with transcriptional regulatory properties. IL-33 binds to and signals through IL1RL1/ST2 and its stimulation recruits MYD88, IRAK1, IRAK4, and TRAF6. IL-33 activates NF-kappaB and MAP kinases, and drives production of TH2-associated cytokines from in vitro polarized TH2 cells. In vivo, IL-33 induces the expression of IL-4, IL-5, and IL-13 and leads to severe pathological changes in mucosal organs. IL-33 is proteolytically converted to a mature form by CASP1 and is highly expressed in high endothelial venules found in tonsils, Peyer's patches and mesenteric lymph nodes and is almost undetectable in placenta. Prolonged IL-33 treatment of mice led to the development of eosinophilia, splenomegaly, and severe pathological changes in mucosal organs such as lungs, esophagus and small intestine. Recent experiments have shown that IL-33 can also co-localize with heterochromatin and possesses transcriptional repressor activities, indicating that IL-33 may function as both a proinflammatory cytokine and an intracellular nuclear factor with transcriptional regulatory properties. Despite its predicted molecular weight, IL-33 will often run at higher molecular weight in SDS-PAGE. Studies have shown that IL-33 can also co-localize with heterochromatin and possesses transcriptional repressor activities, indicating that IL-33 may function as both a proinflammatory cytokine, and an intracellular nuclear factor with transcriptional regulatory properties.