Interleukin 33

Interleukin 33 (IL-33) is a cytokine belonging to the IL-1 superfamily. IL-33 induces helper T cells to produce type 2 cytokines. This cytokine was previously named NF-HEV 'nuclear factor (NF) in high endothelial venules' (HEVs) since it was originally identified in these specialized cells. IL-33 mediates its biological effects by interacting with the receptors ST2 and IL-1 Receptor Accessory Protein, activating intracellular molecules in the NF-κB and MAP kinase signaling pathways that drive production of type 2 cytokines (e.g. IL-4, IL-5 and IL-13) from polarized Th2 cells. The induction of type 2 cytokines by IL-33 in vivo is believed to induce the the severe pathological changes observed in mucosal organs following administration of IL-33.