IL-1 Family Ligands

IL-1 family members include IL-1 alpha, IL-1 beta, IL-1ra, IL-18 and IL-1F5 through F10. All family members show a 12 beta-strand, beta-trefoil configuration, and all family members are believed to have arisen from a common ancestral gene that underwent multiple duplications. IL-1 alpha and IL-1 beta are the products of distinct genes that show approximately 25% amino acid sequence identity, but recognize the same cell surface receptors. Both proteins are produced by a wide variety of cells in response to stimuli such as those produced by inflammatory agents, infections, or microbial endotoxins.