IL-1 beta

Interleukin-1 beta (IL-1beta) is produced by activated macrophages. IL-1beta stimulates thymocyte proliferation by inducing IL-2 release, B-cell maturation and proliferation, and fibroblast growth factor activity. IL-1beta proteins are involved in the inflammatory response, being identified as endogenous pyrogens, and are reported to stimulate the release of prostaglandin and collagenase from synovial cells. IL-1 is a name that designates two pleiotropic cytokines, IL-1 alpha (IL1F1) and IL1 beta (IL1F2), which are the products of distinct genes. IL- 1alpha and IL-1 beta are structurally related polypeptides that share approximately 21% amino acid (aa) identity in human. Both proteins are produced by a wide variety of cells in response to inflammatory agents, infections, or microbial endotoxins. While IL-1 alpha and IL-1 beta are regulated independently, they bind to the same receptor and exert identical biological effects. The human IL-1 beta cDNA encodes a 269 aa precursor. A 116 aa propeptide is cleaved intracellularly by the cysteine protease IL-1 beta converting enzyme (Caspase1/ICE) to generate the active cytokine. The mature human IL-1 beta shares 96% aa sequence identity with rhesus and 67% 78% with canine, cotton rat, equine, feline, mouse, porcine, and rat IL-1 beta. Human recombinant IL-1beta produced in E. coli is a non-glycosylated, IL-1 beta polypeptide chain containing 153 amino acids and having a molecular mass of 17.0 kDa.