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预期应用
ELISA法定量测定人血清、血浆、细胞培养物上清或其它相关液体中sICAM-1 含量。
实验原理
本试剂盒应用双抗体夹心酶标免疫分析法测定标本中可溶性细胞间粘附分子水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入sICAM-1抗原、生物素化的抗人sICAM-1抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的sICAM-1呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。
Intended use
This immunoassay kit allows for the specific measurement of human soluble Intercellular Adhesion Molecule (sICAM) concentrations in cell culture supernates, serum, and plasma.
Introduction
Adhesion molecules mediate the interaction of cells with the extracellular matrix and with other cells. The immunoglobulin superfamily of proteins contains a large class of adhesion molecules with multiple immunoglobulin-like domains. ICAM is a member of this family. It is a 90 kDa type-I transmembrane glycoprotein with five Ig-like extracellular domains. The most important ligands for ICAM-1 are the _2 integrins LFA-1 (CD11a/CD18) and Mac-1 (CD11b/CD18), which are expressed on leukocytes. ICAM-1 thus mediates the adhesion of leukocytes to ICAM-1-expressing cells. ICAM-1 also binds fibrinogen, hyaluronan, Rhinoviruses, Plasmodium falciparum-infected erythrocytes and CD43 (sialophorin)
ICAM-1 is either a transmembrane protein (mICAM-1) or soluble (sICAM-1). mICAM-1 is expressed on endothelial and epithelial cells, lymphocytes, monocytes, eosinophils, keratinocytes, dendritic cells, hematopoietic stem cells, hepatocytes and fibroblasts. Regulation of ICAM-1 expression is cell specific. Up-regulation generally is by inflammatory cytokines (TNF-α, IFN-γand IL-1) and down-regulation generally is by anti-inflammatory agents (e.g.glucocorticoids). One important, well-characterized function of ICAM-1 is immune-cell trafficking. At sites of inflammation, inflammatory cytokines induce up-regulation of ICAM-1 expression on vascular endothelial cells and activation of leukocyte integrins (LFA-1 and Mac-1). This leads to adhesion of leukocytes to the local endothelium, an essential step in migration of leukocytes to the site of inflammation. sICAM-1 has been reported in serum, cerebrospinal fluid and bronchoalveolar lavage. sICAM-1 likely arises by proteolytic cleavage of mICAM-1; synthesis from an alternatively spliced message has not been found. In general, elevated levels of serum sICAM-1 appear to be associated with inflammatory conditions and certain malignancies. It has, however, been pointed out that in inflammatory conditions, where the ligands LFA-1 and Mac-1 are likely to be activated, binding and clearance of sICAM-1 might be enhanced, so that a reciprocal relationship between sICAM-1 levels and inflammation also is possible. |
