Description
IL18 is synthesized as a biologically inactive precursor protein that has limited biological activity. The proform of IL18 is processed by one of the caspases, Caspase-1, to generate the 18 kDa bioactive molecule. IL-18 is produced during the acute immune response by macrophages and immature dendritic cells. Interleukin-18 is expressed by a variety of immune and non-immune cells, including monocytes and macrophages. IL18 is one of the pro- inflammatory cytokines. The activities of IL18 appear to be species specific. An important function of IL18 is the regulation of functionally distinct subsets of T-helper cells required for cell mediated immune responses (Nakanishi et al, 2001). IL18 functions as a growth and differentiation factor for Th1 cells. IL18 up-regulates FAS ligand mediated cytotoxic activitiy of murine natural killer cells. IL-18 is part of a complex regulatory circuit involved in causing cell death by apoptosis