【项目简介】
B7H2,also known as B7related protein (B7RP1), ICOS Ligand, and CD275, is an approximately 60 kDa transmembrane glycoprotein in the B7 family of immune regulatory molecules. Mature human B7H2 consists of a 238 amino acid (aa) extracellular domain (ECD) with two immunoglobulinlike domains, a 21aa transmembrane segment, and a 25aa cytoplasmic domain . Within the ECD, human B7H2 shares 50% and 54%aa sequence identity with mouse and rat B7H2, respectively. Alternative splicing generates a long isoform that carries a 10aa substitution for the Cterminal 3 residues. B7H2 is expressed on antigen presenting cells such as B cells, macrophages, monocytes, and dendritic cells. It binds to ICOS on activated T cells, leading to both positive and negative effects on immune responses including its own downregulation. Mouse and human B7H2 exhibit crossspecies binding to ICOS. The B7H2 interaction with ICOS is costimulatory for T cell proliferation as well as the development of B cells, plasma cells, follicular helper T cells (Tfh) and germinal centers. 

【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B7-H2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B7-H2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B7-H2抗体可与被酶标板捕获的人B7-H2结合，形成“包被抗人B7-H2抗体+人B7-H2+抗人B7-H2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B7-H2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B7-H2的浓度。