IL-33 has been identified as alarmin with a dual function; an IL-1 family cytokine acting extracellularly and intracellularly as nuclear factor regulating gene expression. IL-33 is released to alert the immune system as a first line of defense. It is expressed and released after cell injury to initiate an immune response and to start repair processes by epithelial cells after damage as a result of an inflammatory process. IL-33 activates many immune cells including ILC2, mast cells, eosinophils, basophils, DCs and Th2 cells. This explains the direct relation to allergic inflammation. Besides, IL-33 is implicated infectious diseases like pathogenic infection, cardiovascular disease, IBD and diabetes. IL-33 signals via ST2 (suppression of tumorigenesis 2), a member of the Toll-like/IL1 receptor (TIR domain containing) superfamily. There are 2 forms of ST2 receptor, membrane bound and a soluble form that acts as a decoy receptor. Via IL33/ST2 activation ILC2 cells produce Th2 cytokines such as IL-5&-13. Intracellularly, IL-33 functions as transcriptional repressor of NF-κB mediated gene expression. This makes it an inhibitor of pro-inflammatory signaling.
Immuno assays, Paraffin sections, Western blot
Dilutions to be used depend on detection system applied. It is recommended that users test the reagent and determine their own optimal dilutions. The typical starting working dilution is 1:50.