Interleukin 33 (IL-33) is a member of the IL-1 cytokine family and is constitutively expressed in smooth muscle and airway epithelial cells. IL-33 signals through the interleukin 1 receptor-like 1 (IL-1R1) and interleukin-1 receptor accessory protein (IL1RAP) receptors to ativate NF-?B and MAPK signaling pathways. IL-33 functions to induce type 2 cytokine production in polarized Type 2 helper T (Th2) cells.
Bioactivity Assay:D10S cell proliferation; ED50 =2 ng/mL; Bioactivity =5.0 x 10^5 units/mg