ABSTRACT
During the course of an infectious disease, most microbial pathogens interact with host tissues in some fashion. This interaction can be of a direct nature, by binding receptors found on host cells, or by binding secreted components that may either immobilize the microorganism at an extracellular site or promote adhesion to host cells. The interaction of microbial pathogens with integrin receptors will be analyzed, with particular focus on the Yersinia pseudotuberculosis invasin protein. The earliest evidence that microorganisms could interact at an indirect level with integrin receptors came from studies demonstrating that a variety of microbial pathogens bind extracellular matrix components, such as fibronectin, which in turn bind integrins. Integrins are associated with some major aspects of microbial uptake by phagocytic cells. The fact that both phagocytic and nonphagocytic cells use members of the identical receptor family to internalize microorganisms is consistent with the notion that they share a common mechanism for uptake of particles.
