The IL-1 family is integral to innate inflammation and reducing inflammation, helping facilitate specific immunological responses. The IL-1 family is initially translated as precursors, lacking signal peptides for secretion. These precursors exist in the cytosol and following cell death by necrosis, are released and activated by extracellular processing (giving rise to their being termed alarmins.) IL-1 receptor antagonist (IL-1Ra) is produced to dampen IL-1 responses, outcompeting the IL-1 family at its receptors. The IL-1 family contains a common Toll-IL-1-receptor (T1R) domain, being the key functional domain. Produced by activated macrophages, IL-1α stimulates thymocyte proliferation by inducing IL-2 release, B-cell maturation and proliferation, and fibroblast growth factor activity. IL-1 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.