Antibodies against Platelet Membrane Glycoproteins II. INFLUENCE ON ADP- AND COLLAGEN-INDUCED PLATELET AGGREGATION, CROSSED IMMUNOELECTROPHORESIS STUDIES AND RELEVANCE TO GLANZMANN'S THROMBASTHENIA

Abstract

In Glanzmann''s thrombasthenia [in human] glycoproteins IIb and IIIa are missing or strongly reduced and aggregation to ADP, collagen and thrombin is impaired. Antibodies against glycoproteins IIb and IIIa did not entirely induce a thrombasthenia-like state in normal platelets. They did strongly inhibit collagen-induced aggregation and inhibited the 2nd wave of aggregation induced by ADP. Crossed immunoelectrophoresis studies using Triton X-100 extracts of whole platelets with these antibodies gave a single immunoprecipitate. This immunoprecipitate was absent when similar studies were carried out with thrombasthenic platelets. Platelet antibodies gave a number of immunoprecipitates with normal platelets and differences were observed with thrombasthenic platelets the most notable of which was a marked reduction in 1 of the major immunoprecipitates. Glycoproteins IIb and IIIa apparently are involved in the later stages of platelet aggregation.