【项目简介】
Human T-cell surface glycoprotein CD8alpha chain, also known as CD8a, is a single-pass type I membrane protein. The CD8 glycoprotein is expressed by thymocytes, mature T cells and natural killer (NK) cells and has been implicated in the recognition of monomorphic determinants on major histocompatibility complex (MHC) Class I antigens, and in signal transduction during the course of T-cell activation. Both human and rodent CD8 antigens are comprised of two distinct polypeptidechains, alpha and beta. The Ig domains of CD8alpha are involved in controlling the ability of CD8 to be expressed. Mutation of B-and F-strand cysteine residues in CD8alpha reduced the ability of the protein to fold properly and, therefore, to be expressed. Defects in CD8A are a cause of familial CD8 deficiency. Familial CD8 deficiency is a novel autosomal recessive immunologic defect characterized by absence of CD8+cells, leading to recurrent bacterial infections.

【检验原理】
本试剂盒采用双抗体夹心ELISA法。酶标微孔板上预包被有抗人CD8a抗体，当加入标准品和待测样本时，标准品和待测样本中的人CD8a会和该抗体结合。洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的的抗人CD8a抗体可与被酶标板捕获的人CD8a结合，形成“包被抗人CD8a抗体+人CD8a+抗人CD8a抗体-HRP”免疫复合物。当加入TMB显色底物后，复合物上连接的HRP催化底物反应，生成蓝色产物，终止反应后变为黄色。在450nm处测定OD值，人CD8a浓度与OD450值之间呈正比，可通过绘制标准曲线求出标本中人CD8a的浓度。