The cell-adhesion molecules

Abstract

The cell-adhesion proteins mediate the early stages of leukocyte recruitment from the blood stream to the sites of tissue damage. Selectins are multifunctional adhesion molecules that mediate the initial interactions between circulating leukocytes and cells of the endothelium. First identified over a decade ago, selectins have provided insight into areas as diverse as normal lymphocyte homing, leukocyte recruitment during inflammatory responses, carbohydrate ligand biosynthesis and adhesion mediated signalling. Three major events occur during the inflammatory response; increasing of blood flow into the affected area, using of capillary permeability and leukocytes migrate from the capillary vessels into the surrounding interstitial spaces to the site of inflammation or injury. The inflammatory response represents complex biological and biochemical process involving cells of the immune system and a plethora of biological mediators. Cell-to-cell communication molecules known collectively as cytokines play an extremely important role in mediating the process of inflammation. Cell-adhesion molecules play a major role in various pathological states. Multiple signal transduction pathways have been described that modulate the adhesion process. These pathways have been studied in great detail for integrins and cadherins two major adhesion systems controlling cell-cell and cell-substrate interactions. Selectins (P, E and L) and their ligands (mainly P-selectin ligand) are necessary to roll and bind of leukocytes on the vascular wall. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as well as some of the integfins, induce firm adhesion of inflammatory cells at the vascular surface. Platelet endothelial cellular adhesion molecule-1 (PECAM-1) are required for extravasation of cells from the blood compartment into the vessel and underlying tissue. Further research is needed to firmly establish the potential clinical and therapeutic utilities of (soluble) adhesion molecules. These study results in both fields will increase our informations about therapeutic targets of adhesion molecules.