Initial Steps of Cell-Substrate Adhesion

Abstract

The decisive step of receptor-mediated cell adhesion may well be the formation of the first bond following contact between a cell and an adhesive surface. Indeed, after the first receptor-ligand association occurred, two limiting situations may be considered. If the rate of bond formation between surfaces maintained in contact by the first linkage is higher than the rate of bond dissociation, the number of cell-surface bonds will increase, making adhesion irreversible in absence of significant disruptive forces or active cell detachment behavior. Conversely, if the rate of bond formation is lower than the rate of bond dissociation, most bonds will not be conducive to durable attachment. Indeed, when rat thymocytes were agglutinated by varying minimal amounts of concanavalin A, the adhesion efficiency was found to be proportional to the first power of the lectin concentration (Capo et al., 1982), thus supporting the view that the rate limiting step was the formation of the first bond.