Extracellular matrix proteins and leukocyte function.

Extracellular matrix (ECM) proteins profoundly affect physiological functioning at the cellular level. Cell growth and differentiation, as well as cell shape and migration via the cytoskeleton, are all affected by ECM proteins. Leukocyte interactions with matrices have recently become an exciting field of research because a number of different leukocyte functions are significantly affected by their binding to ECM proteins. This may be especially important in inflammatory responses where leukocytes are primed for inflammatory mediator and cytokine production by binding to ECM proteins during extravasation. Because activated leukocytes produce potentially damaging substances, the progress of an inflammatory response can be profoundly affected by the ECM proteins encountered by leukocytes during their migration from within the peripheral circulation to sites of inflammation. This review summarizes recent publications describing components of the ECM that influence leukocyte function, the receptors involved in leukocyte binding to ECM proteins, and focuses on the effects of ECM proteins on the production of inflammatory mediators and cytokines by human peripheral blood leukocytes.