IL-5 is a TH2 cell cytokine consisting of 115 amino acids (133 in mice) and is part of the hematopoietic family. Unlike other members of this cytokine family (such as interleukin 3 and GM-CSF), the active form of this glycoprotein is a homodimer. The IL-5 receptor (IL-5R) belongs to the type I cytokine receptor family, forming a heterodimer composed of two peptide chains. One α subunit binds to IL-5, conferring cytokine specificity to the receptor cell, while the other β subunit, containing a signal transduction domain, does not bind to IL-5.Signal transduction by IL-5 mainly occurs through the JAK/STAT pathway. Upon binding of IL-5 with IL-5Rα, JAK family members are activated, followed by phosphorylation of STAT1, STAT3, and STAT5, eventually regulating gene expression in the nucleus.For a long time, IL-5 has been associated with various allergic diseases, including allergic rhinitis and asthma, where a significant increase in circulating, airway tissue, and induced sputum eosinophil counts is observed. Given the high consistency of eosinophils, particularly in allergic asthma pathology, it is widely speculated that eosinophils play a crucial role in the pathology of this disease.The IL-5 Reporter 293 Cell Line is a luciferase reporter gene cell line constructed based on the JAK-STAT signaling pathway. Upon binding of the IL-5 receptor, the STATs signaling pathway is activated, leading to the expression of luciferase. The luciferase readout represents the activation effect of the signaling pathway and can therefore be used for in vitro evaluation of IL-5-related drugs.
