Protein. Human IL-33 aa 112-270 is untagged. Amino acids C208 and C232 have been mutated to serine to protect IL-33 from oxidation. Source E. coli. Endotoxin content <0.01EU/µg purified protein LAL test Lonza. Lyophilized. Contains PBS. Binds to human ST2. Purity >95% SDS-PAGE. Interleukin-33 IL-33 HF-NEV IL-1F11, a member of the IL-1 family of cytokines, is expressed by many cell types following pro-inflammatory stimulation and is thought to be released upon cell lysis. IL-33 binds to and signals through ST2 IL-1R1 and its stimulation recruits MYD88, IRAK, IRAK4 and TRAF6, followed by phosphorylation of ERK1 MAPK3 / ERK2 MAPK1, p38 MAPK14 and JNK. The ability of IL-33 to target numerous immune cell types, like Th2-like cells, mast cells and B1 cells, and to induce cytokine and chemokine production underlines its potential in influencing the outcome of a wide range of diseases, such as arthritis.