Interleukin-17A (IL-17A) is a 35 kDa pro-inflammatory cytokine and a member of the IL-17 family. Alongside IL-17A, five additional homologous cytokines have been identified —IL-17B through IL-17F. Despite their structural similarities, these cytokines exhibit no sequence homology with other known cytokine families and demonstrate remarkable conservation across mammalian species, particularly between human and mouse homologs. IL-17A is characterized by its pivotal role in mediating immune responses and inflammation. IL-17A exerts its biological effects through binding to its receptor, IL-17 receptor, which is widely expressed on various cell types, including epithelial cells, endothelial cells, fibroblasts, and immune cells. Upon stimulation by various pathogens or inflammatory signals, cells release IL-17A, which modulates downstream signaling pathways, such as the NF-κB and MAPK pathways, leading to the production of pro-inflammatory proteins, including cytokines, chemokines, and matrix metalloproteinases. These mediators promote inflammation, tissue infiltration by immune cells, and tissue damage, contributing to the pathogenesis of various inflammatory and autoimmune diseases.

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