FIBRONECTIN ENHANCES THE MIGRATION RATE OF HUMAN NEUTROPHILS IN-VITRO

Efficient polymorphonuclear neutrophil (PMN) migration depends on spec ific interactions between PMNs, endothelial cells, and extracellular m atrix (ECM) proteins, We investigated the relationship between PMN mig ration and the ECM molecule fibronectin (FN), We used an in vitro migr ation assay system to show that human PMNs migrated across an FN-coate d filter barrier toward a formyl-Met-Leu-Phe (fMLP) chemoattractant gr adient in greater numbers than across (uncoated) bare filters. In 1 h of fMLP stimulation, 69 +/- 6% of the PMNs had migrated across the FN- coated filters, whereas 46 +/- 5% of PMNs migrated across bare filters . This effect was specific to FN; coating the filters with the ECM pro tein vitronectin did not enhance migration. Monoclonal antibodies agai nst FN or against the alpha(5) or beta(1) integrin subunits of the FN receptor inhibited the enhanced PMN migration response across FN-coate d filters. These findings indicate that the extracellular matrix prote in FN enhances PMN migration and that this response is mediated by the alpha(5) beta(1) FN receptor.