TNF-sR2 ELISA measures the soluble receptor 2 of TNF α in biologic samples of human origin. The 55-kD TNFαR1 and 75-kD TNF αR2 are specific cell surface receptors for TNF α, a transmembrane inflammatory-mediating cytokine, that elicit TNF-mediated responses through activation of cell signaling pathways. TNF α and its receptors are shed from the cell surface, with TNF α appearing in the plasma as free cytokine or bound to circulating receptors released into the extracellular space. Circulating concentrations of TNF αR2 have been found to be associated with cardiovascular and renal disease, and particularly with the development of chronic kidney disease in diabetes.
To complete the assay, standard or sample containing TNF-sR2 in the soluble phase is added to microtiter wells coated with anti-receptor antibody. The TNF-sR2 in standard or sample is captured by this antibody on the solid phase, and unbound materials are washed away. Biotinylated anti- receptor antibody is then added, followed by a reaction with Streptavidin –HRP conjugate to label the biotinylated probe with enzyme. After washing, TNF-sR2 bound to the capture antibody on the stationary phase is detected with the addition of a chromogenic substrate. Samples with absorbance values above the standard curve should be diluted before assay.