Hamster Anti-Mouse TNFRSF1B monoclonal antibody for ELISA(Cap), FC, WB. Two types of soluble TNF receptors have been identified in human serum and urine which can neutralize the biological activities of TNF-alpha and TNF-beta. These binding proteins represent truncated forms of the two types of high-affinity cell surface receptors for TNF (TNFR-p60 Type B and TNFR-p80 Type A). Soluble TNF RII corresponds to TNFR-p80 Type A. In the new TNF superfamily nomenclature, TNF RII is referred to as TNFRSF1B. These apparent soluble forms of the receptors appear to arise as a result of shedding of the extracellular domains of the membrane-bound receptors. Normal concentrations as high as 4 ng/mL are found in the serum of healthy individuals, and even higher levels may be found in some pathological conditions. Although the physiological role of these proteins is not known, it has been speculated that shedding of the soluble receptors in response to TNF release could serve as a mechanism to scavenge the TNF not immediately bound and thus localize the inflammatory response. It is also possible that the pool of TNF bound to soluble receptors could represent a reservoir for the controlled release of TNF.