【项目简介】
T-cell surface glycoprotein CD3 delta chain, also known as CD3D, is a single-pass type I membrane protein. CD3D, together with CD3-gamma, CD3-epsilon and CD3-zeta, and the T-cell receptor alpha/beta and gamma/delta heterodimers, forms the T cell receptor-CD3 complex. The majority of T cell receptor (TCR) complexes in mice and humans consist of a heterodimer of polymorphic TCRalpha and beta chains along with invariant CD3gamma, delta, epsilon, and zeta chains. CD3 chains are present as CD3gammaepsilon, deltaepsilon, and zetazeta dimers in the receptor complex and play critical roles in the antigen receptor assembly, transport to the cell surface, and the receptor-mediated signal transduction. T cell receptor-CD3 complex plays an important role in coupling antigen recognition to several intracellular signal-transduction pathways. This complex is critical for T-cell development and function, and represents one of the most complex transmembrane receptors. The T cell receptor-CD3 complex is unique in having ten cytoplasmic immunoreceptor tyrosine-based activation motifs (ITAMs). CD3D contains 1 ITAM domain and has been shown to interact with CD8A. 

【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CD3d 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CD3d 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CD3d 抗体可与被酶标板捕获的人CD3d 结合，形成“包被抗人CD3d 抗体+人CD3d +抗人CD3d 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CD3d 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CD3d 的浓度。