IL-1ra/IL-1F3: Proteins and Enzymes

IL-1ra (IL-1 receptor antagonist) is a widely expressed acute phase protein that serves to dampen inflammation. IL-1ra binds to both IL-1 RI and IL-1 RII. It competitively inhibits IL-1 (alpha or beta) binding to IL-1 RI and does not trigger recruitment of the accessory molecule IL-1 R AcP or activation of IL-1 RI signaling. IL-1ra blocks the proinflammatory actions of IL-1 including Prostaglandin E2 and IL-6 release from endothelial cells, fever generation, thrombocytosis, the production of hepatic acute phase proteins, and neutrophil expansion and infiltration.