VESICLE-VESICLE ADHESION BY MOBILE LOCK-AND-KEY MOLECULES - DEBYE-HUCKEL THEORY AND MONTE-CARLO SIMULATION

Adhesion between cells is due to formation of weak, reversible chemica l bonds between ''lock'' and ''key'' molecules imbedded in the cell su rfaces. In this paper we present a theory for cell adhesion that exten ds the well-known Bell model of noninteracting adhesion molecules to i nclude the cell-surface mediated elastic coupling between the molecule s. We show that the statistical mechanics of this many-body problem ca n be mapped onto that of the two-dimensional Coulomb plasma with attra ctive forces. Using this mapping we find the following results: (i) th e ideal-mixing state assumed by Bell and co-workers [Science 200, 618 (1978); Biophys. J. 45, 1051 (1984)] is unstable against migration of adhesion molecules to the rim of the adhesion disk in agreement with e xperimental observations and (ii) loss of adhesion is generally preced ed by the collapse of the adhesion disk into a ''stress-focused'' stat e with enhanced adhesive strength.