Vesicle-vesicle adhesion by mobile lock-and-key molecules: Debye-Hückel theory and Monte Carlo simulation

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Abstract
Adhesion between cells is due to formation of weak, reversible chemical bonds between ''lock'' and ''key'' molecules imbedded in the cell surfaces. In this paper we present a theory for cell adhesion that extends the well-known Bell model of noninteracting adhesion molecules to include the cell-surface mediated elastic coupling between the molecules. We show that the statistical mechanics of this many-body problem can be mapped onto that of the two-dimensional Coulomb plasma with attractive forces. Using this mapping we find the following results: ~i! the 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 experimental observations and ~ii! loss of adhesion is generally preceded by the collapse of the adhesion disk into a ''stress-focused'' state with enhanced adhesive strength. @S1063-651X~98!08901-6#