Human Cluster of Differentiation 8, CD8 ELISA Kit

Product Description

INTRODUCTION CD8 (cluster of differentiation 8) is a transmembrane glycoprotein that serves as a co-receptor for the T cell receptor (TCR). Like the TCR, CD8 binds to a major histocompatibility complex (MHC) molecule, but is specific for the class I MHC protein. There are two isoforms of the protein, alpha and beta, each encoded by a different gene. In humans, both genes are located on chromosome 2 in position 2p*2. The extracellular IgV-like domain of CD*-α interacts with to the α3 portion of the Class I MHC molecule. This affinity keeps the T cell receptor of the cytotoxic T cell and the target cell bound closely together during antigen-specific activation. Cytotoxic T cells with CD8 surface protein are called CD8+ T cells. The main recognition site is a flexible loop at the a3 domain of an MHC molecule. This was discovered by doing mutational analyses. The flexible a3 domain is located between residues **3 and **9 in the genome. PRINCIPLE OF THE ASSAY The microtiter plate provided in this kit has been pre-coated with an antibody specific to CD8. Standards or samples are then added to 3 the appropriate microtiter plate wells with a biotin-conjugated antibody preparation specific for CD8 and Avidin conjugated to Horseradish Peroxidase (HRP) is added to each 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 CD8, biotin-conjugated antibody and enzyme-conjugated Avidin will exhibit a change in color. The enzyme-substrate reaction is terminated by the addition of a sulphuric acid solution and the color change is measured spectrophotometrically at a wavelength of **0 nm ± 2 nm. The concentration of CD8 in the samples is then determined by comparing the O.D. of the samples to the standard curve.