sIL1RII

sIL1RII, also known as soluble Interleukin-1 Receptor Type II, is a truncated form of the Interleukin-1 Receptor Type II (IL-1RII) protein. IL-1RII is a transmembrane receptor that plays a role in the inflammatory response by binding to Interleukin-1 (IL-1) cytokines, specifically IL-1 alpha and IL-1 beta. These cytokines are potent mediators of inflammation, immunity, and cellular processes.

The soluble form, sIL1RII, is generated through proteolytic cleavage of the membrane-bound IL-1RII or by alternative splicing. Unlike the membrane-bound receptor, sIL1RII lacks the intracellular signaling domain, meaning it cannot initiate downstream signaling pathways. Instead, it functions as a decoy receptor.

sIL1RII circulates in biological fluids, such as serum and urine. Its primary proposed function is to bind to free IL-1 cytokines in the extracellular space, thereby neutralizing their activity and preventing them from engaging with the functional membrane-bound IL-1 receptors. This can help to dampen or regulate inflammatory responses. Elevated levels of sIL1RII have been observed in various inflammatory and autoimmune conditions, suggesting a potential role in disease pathogenesis or as a biomarker. Research continues to explore its precise physiological roles and therapeutic potential.