【项目简介】
CD40, also known as TNFRSF5, is a member of the TNF receptor superfamily which are single transmembrane-spanning glycoproteins. CD40 protein plays an essential role in mediating a broad variety of immune and inflammatory responses including T cell-dependent immunoglobulin class switching, memory B cell development, and germinal center formation. CD40 protein is expressed in B cells, dendritic cells, macrophages, endothelial cells, and several tumor cell lines. Defects in CD40 result in hyper-IgM immunodeficiency type 3 (HIGM3). In addition, CD40/CD40L interaction is found to be necessary for amyloid-beta-induced microglial activation, and thus is thought to be an early event in Alzheimer disease pathogenesis.

【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CD40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CD40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CD40抗体可与被酶标板捕获的人CD40结合，形成“包被抗人CD40抗体+人CD40+抗人CD40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CD40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CD40的浓度。