protein_function: Cytokine that binds to and signals through theIL1RL1,ST2 receptor which in turn activates NF-kappa-B and MAPKsignaling pathways in target cells (PubMed:16286016). Involved inthe maturation of Th2 cells inducing the secretion of T-helpertype 2-associated cytokines. Also involved in activation of mastcells, basophils, eosinophils and natural killer cells. Acts as achemoattractant for Th2 cells, and may function as an "e;alarmin"e;,that amplifies immune responses during tissue injury(PubMed:17853410, PubMed:18836528)..
Interleukin 33(IL-33) is a cytokine belonging to the IL-1 superfamily. The IL33 gene maps to chromosome 9p24.1 by using of genomic database analysis. Recombinant mature human IL33 bound to ST2. The induction of type 2 cytokines by IL-33 in vivo is believed to induce the severe pathological changes observed in mucosal organs following administration of IL-33. IL33, an alarmin released from necrotic cells, is necessary for potent CD8 + T cell(CTL) responses to replicating, prototypic RNA, and DNA viruses in mice. IL33 prevented the downregulation of CXCR2 and inhibition of chemotaxis induced by activation of TLR4, and found that IL33 reverses the TLR4-induced reduction of CXCR2 expression via the inhibition of expression of GRK2.