Johnson-Léger C, Aurrand-Lions M, Imhof B A
Department of Pathology, Centre Médical Universitaire, Switzerland.
J Cell Sci. 2000 Mar;113 ( Pt 6):921-33. doi: 10.1242/jcs.113.6.921.
Leukocyte extravasation from the blood across the endothelium is vital for the functioning of the immune system. Our understanding of the early steps of this process has developed rapidly. However, it is still unclear how leukocytes undergo the final step, migrating through the junctions that mediate adhesion between adjacent endothelial cells, while preserving the barrier function of the endothelium. The first stage of transmigration - tethering and rolling - is mediated by interactions between selectins on the surface of leukocytes and glycosylated proteins such as GlyCAM-1 on the surface of endothelial cells. Stimulation of the leukocyte by chemokines then induces tight adhesion, which involves binding of activated leukocyte integrins to endothelial ICAM-1/VCAM-1 molecules. Passage of the leukocyte across the endothelium appears to require delocalization of certain endothelial cell molecules and proteolytic degradation of junctional complexes.
白细胞从血液中穿过内皮细胞渗出对于免疫系统的正常运作至关重要。我们对这一过程早期步骤的理解发展迅速。然而，目前仍不清楚白细胞如何经历最后一步，即穿过介导相邻内皮细胞间黏附的连接，同时保持内皮细胞的屏障功能。迁移的第一阶段——拴系和滚动——由白细胞表面的选择素与内皮细胞表面糖基化蛋白（如GlyCAM-1）之间的相互作用介导。趋化因子对白细胞的刺激随后诱导紧密黏附，这涉及活化的白细胞整合素与内皮细胞ICAM-1/VCAM-1分子的结合。白细胞穿过内皮似乎需要某些内皮细胞分子的去定位以及连接复合体的蛋白水解降解。
