【项目简介】
beta -Defensin 3，also known as BD-3 and DEFB-3，is a membrane-active cationic peptide that functions in inflammation and innate immune responses。There are at least 30 beta-Defensins which are distinguished from alpha-Defensins by the connectivity pattern of their three intramolecular disulfide bonds。The 45 amino acid (aa) mature human BD-3 shares 38% and 33% aa sequence identity with mouse and rat BD-3，respectively。It shares 18%-36% aa sequence identity with other human beta-Defensins。BD-3 is widely expressed among epithelial tissues, notably by keratinocytes and airway epithelial cells。It is upregulated in response to proinflammatory cytokines，microbial and viral infections, and at the edges of skin wounds。BD-3 displays strain specific microbicidal activity toward a broad spectrum of bacteria and yeast。BD3 also induces monocyte migration，mast cell activation，and a mast cell-dependent increase in vascular permeability。

【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BD-3抗体，当加入标准品和待测样本时，重组或天然的人BD-3会和该抗体结合。洗板后，游离的其他成分被洗去，加入生物素化的抗人BD-3抗体可与被酶标板捕获的人BD-3结合。再次洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的链霉亲和素，生物素和链霉亲和素特异性结合，形成“包被抗人BD-3抗体+人BD-3+生物素化抗人BD-3抗体+链霉亲和素-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BD-3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BD-3的浓度。