The role of carbohydrate in platelet adhesion to foreign surfaces

A mechanism of platelet adhesion to foreign surfaces is proposed which involves the formation of enzyme‐substrate complex bridges between platelet glycosyl transferases and surface‐adsorbed glycoproteins. To test this hypothesis two experimental approaches were attempted. The first, in vitro, series of experiments assayed two glycosyl transferases using adsorbed plasma proteins as acceptors. Sugar‐nucleotides could be transferred onto adsorbed gamma globulin and fibrinogen but not onto adsorbed albumin. The second group of experiments quantitated platelets adhering to tubing coated with protein and subjected to treatment to remove different carbohydrate residues. Using whole unheparinized ovine blood, more platelets adhered to fibrinogen or gamma globulin coatings which had been either desialyzed or had both sialic acid and galactose removed than to the same coatings when untreated. These data, plus that of other workers, give support to the proposed mechanism.