Detection of glycoprotein IIb and IIIa by monoclonal antibodies

Abstract

Murine monoclonal antibodies were produced against human platelet membranes and screened on platelets by a 125I protein A radioimmunoassay. Several clones produced platelet specific antibodies as they showed no reaction with peripheral blood lymphocytes, neutrophils, bone marrow (excluding megkaryocytes) or several cell lines. Two antibodies (designated anti-HuPl-m1a and anti-HuPl-m1b) were of particular interest in that although platelet specific they were non-reactive with platelets from a thrombasthenic patient. In functional assays these two antibodies could specifically inhibit ADP and collagen induced aggregation of platelets and release of ATP, retard platelet aggregation and ATP release induced by epinephrine, and inhibit ADP induced platelet fibrinogen binding. These two antibodies appear to recognize glycoproteins IIb and IIIa as analysis by SDS-PAGE using radiolabelled membranes revealed a two chain structure of molecular weight 112000 and 122000 daltons when run after reduction and 87000 and 140000 daltons non-reduced.