Human TNF-R1

Two types of soluble TNF receptors (sTNF-R1 and sTNF-R2) have been identified which act to neutralize the biological activities of TNF alpha and TNF beta. Levels of these soluble receptors appear to arise as a result of shedding of the extracellular domains of the membrane bound receptors. Elevated levels of soluble TNF receptors have been found in the amniotic fluid of pregnant women. Recombinant sTNF-R1 comprises a 161 amino acid fragment (41-201) corresponding to the mature TNF-R1 protein and is expressed in E. coli with an amino-terminal hexahistidine tag.