The function of Ensembl gene identifier ENSG00000166090 (IL25, interleukin 25) is as follows. Cytokine produced by various cells such as eosinophils, T- helper type 2 (Th2) cells or epithelial cells that plays a role in internal safety of adaptive immune responses by regulating cytokine production (PubMed:15860795, PubMed:25821217). Promotes and augments T- helper type 2 responses locally or systemically (PubMed:25821217). Exerts its activity via its receptor composed of IL17RA and IL17RB for signal transduction (By similarity). In turn, stimulates the JAK2- STAT5A pathway and promotes the secretion of type-2 associated cytokines including IL4, IL9 and IL13 (PubMed:25821217). Also induces the release of IL8, and IL6 from eosinophils through the combined activation of MAPK and NF-kappa-B pathways (PubMed:15860795). Inhibits the differentiation of T-helper (Th17) cells via the production of IL4, IL5 and IL13 (PubMed:11754819). {ECO:0000250|UniProtKB:Q8VHH8, ECO:0000269|PubMed:11754819, ECO:0000269|PubMed:15860795, ECO:0000269|PubMed:25821217}.