Interleukin-17 is a proinflammatory cytokine produced by activated T cells. IL-17 regulates the activities of NF-kappa B and mitogen-activated protein kinases. IL17 can stimulate the expression of IL6 and cyclooxygenase-2 (PTGS2/COX-2), as well as enhance the production of nitric oxide (NO). High levels of IL-17 are associated with several chronic inflammatory diseases including rheumatoid arthritis, psoriasis and multiple sclerosis. The original described IL-17 protein, now known as IL-17A, was identified from a CD4+ T cells DNA library. IL-17 can be induced from primary peripheral blood CD4+ T cells upon stimulation. Supernatant from cells transfected with IL-17 induced IL-16 and IL-18 production and enhanced the surface expression of the intracellular adhesion molecule-1 (ICAM-1) in human fibroblasts.
