Description
Introduction: Beta-2 microglobulin also known as B2M is a component of MHCclass I molecules, which are present on almost all cells of thebody (red blood cells are a notable exception). Beat-2microglobulin lies lateral to the alpha3 chain on the cell surface.Unlike alpha3, beta2 has no transmembrane region. Directly above beta2(i.e. away from the cell) lies the alpha1 chain, which itself is lateral tothe alpha2. Beta-2 microglobulin associates not only with the alphachain of MHC class I molecules, but also with class I-likemolecules such as CD1 and Qa. Beta-2 microglobulin isnecessary for cell surface expression of MHC class I and stabilityof the peptide binding groove. In fact, in the absence of beta2microglobulin, very limited amounts of MHC class I (classical andnon-classical) molecules can be detected on the surface. In theabsence of MHC class I, CD8 T cells cannot develop.
Principle of the Assay: The microtiter plate provided in this kit has been pre-coated withan antibody specific to BMG. Standards or samples are thenadded to the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for BMG andAvidin conjugated to Horseradish Peroxidase (HRP) is added toeach microplate well and incubated. Then a TMB (3,3',5,5'tetramethyl-benzidine) substrate solution is added to each well.Only those wells that contain BMG, biotin-conjugated antibodyand enzyme-conjugated Avidin will exhibit a change in color. Theenzyme-substrate reaction is terminated by the addition of asulphuric acid solution and the color change is measuredspectrophotometrically at a wavelength of 450 nm +/- 2 nm. Theconcentration of BMG in the samples is then determined bycomparing the O.D. of the samples to the standard curve