Binding of plasma fibronectin to monolayer human endothelium

Interaction of exogenous plasma fibronectin with endothelium was examined using monolayer cultures of human umbilical vein endothelial cells. Plasma fibronectin was purified on gelatin-sepharose with 1 M arginine elution and iodinated with 125I by the solid phase glycoluril method. Endothelial monolayers were incubated with 0.5 to 15.0 mg/l (125I)fibronectin. Specificity of binding was 50 to 60% as determined by competition with 50-fold excess nonlabeled fibronectin. Binding reached maximal levels within 1 hour and without saturation over the concentration range. The bound glycoprotein showed minimal dissociation during subsequent incubation in media free of fibronectin.