Muller W A
Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York, NY 10021, USA.
J Leukoc Biol. 1995 Apr;57(4):523-8. doi: 10.1002/jlb.57.4.523.
Platelet/endothelial cell adhesion molecule-1 (PECAM-1, CD31) is a molecule capable of mediating both homophilic and heterophilic adhesion. It is constitutively expressed and concentrated in the lateral borders between endothelial cells and expressed on the surfaces of neutrophils, monocytes, and some T cell subsets, as well as on platelets. In a quantitative in vitro assay, monoclonal antibody against PECAM-1 or soluble recombinant PECAM-1 selectively blocked passage of both neutrophils and monocytes across the endothelial monolayer by 70-90% without interfering with the ability of these cells to bind to the apical endothelial cell surface. These regents worked whether directed against leukocyte PECAM-1 or against endothelial cell PECAM-1 and were not additive, suggesting that a homophilic interaction was occurring. In a murine model of acute inflammation, thioglycollate-induced peritonitis, a monoclonal antibody against mouse PECAM-1 blocked emigration of leukocytes into the peritoneal cavity down to background levels. Examination of peritoneal venules in these mice revealed many leukocytes in apparent contact with the endothelial surface but unable to cross the intima. Thus, PECAM-1 has a distinct role in the transendothelial migration phase of leukocyte emigration, independent of the adhesion events on the apical surface.
血小板/内皮细胞黏附分子-1（PECAM-1，CD31）是一种能够介导同型和异型黏附的分子。它组成性表达并集中在内皮细胞之间的侧向边界，在中性粒细胞、单核细胞和一些T细胞亚群的表面以及血小板上也有表达。在一项定量体外试验中，抗PECAM-1单克隆抗体或可溶性重组PECAM-1可选择性地使中性粒细胞和单核细胞穿过内皮单层的通过率降低70%-90%，而不干扰这些细胞与内皮细胞顶端表面结合的能力。这些试剂无论是针对白细胞PECAM-1还是内皮细胞PECAM-1都起作用，且没有累加效应，这表明发生了同型相互作用。在急性炎症的小鼠模型——巯基乙酸盐诱导的腹膜炎中，抗小鼠PECAM-1单克隆抗体可将白细胞向腹腔的迁移阻断至背景水平。对这些小鼠的腹膜小静脉进行检查发现，许多白细胞明显与内皮表面接触，但无法穿过内膜。因此，PECAM-1在白细胞渗出的跨内皮迁移阶段具有独特作用，独立于顶端表面的黏附事件。
