【项目简介】
MICB (MHC class I chainrelated gene B) is a transmembrane glycoprotein that functions as a ligand for NKG2D. A closely related protein, MICA, shares 85% amino acid identity with MICB. These 2 proteins are distantly related to the MHC class I proteins. MICA and MICB (MICA/B) possess three extracellular immunoglobulinlike domains, but have no capacity to bind peptide or interact with β2microglobulin. The genes encoding MICA/B are found within the major histocompatibility complex on human chromosome 6. The MICB locus is polymorphic with more than 15 recognized human alleles. MICA/B are minimally expressed on normal cells, but are frequently expressed on epithelial tumors and can be induced by bacterial and viral infections. MICA/B are ligands for NKG2D, an activating receptor expressed on NK cells, NKT cells, γδ T cells, and CD8+ αβ T cells. Recognition of MICA/B by NKG2D results in the activation of cytolytic activity and/or cytokine production by these effector cells. MICA/B recognition is involved in tumor surveillance, viral infections, and autoimmune diseases. The release of soluble forms of MICA/B from tumors downregulates NKG2D surface expression on effector cells resulting in the impairment of antitumor immune response.
 
【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MICB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MICB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MICB抗体可与被酶标板捕获的人MICB结合，形成“包被抗人MICB抗体+人MICB+抗人MICB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MICB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MICB的浓度。