The Effect of Platelet Membrane Antibodies on Aggregation and Release

S ummary . Human platelets were preincubated with Fab fiagments derived from two types of platelet antibodies: (1) antibody to whole platelet membranes, and (2) antibody to the major platelet membrane glycoprotein. Subsequently platelet aggregation and release of 14 Cserotonin in response to adenosine diphosphate (ADP), adrenaline, thrombin, and collagen were evaluated. Following incubation with the anti‐membrane antibody, significant inhibition of both aggregation and serotonin release was observed. The pattern of inhibition of ADP‐ and thrombin‐induced aggregation and release differed from the inhibition noted after the addition of adrenaline or collagen. Treatment of platelets with the anti‐membrane glycoprotein antibody had no effect on subsequent aggregation induced by ADP, adrenaline, thrombin or collagen.