title: Alloantibody-induced platelet serotonin release is blocked by antibody to the platelet PLA1 antigen.
abstract: Anti-platelet antibodies are known to activate the platelet release mechanism, usually measured by [14C]serotonin secretion. We have made immunoglobulin preparations of antibodies to HLA antigens, blood group A and platelet-specific PlA1 antigen on the platelet surface and have defined the optimal conditions for [14C]serotonin secretion by washed platelets. For optimal [14C]serotonin release, platelets were washed in apyrase and suspended in Tyrode-albumin with Ca++ and Mg++ and fibrinogen. Anti-PlA1 at high concentration did not cause [14C]serotonin release and inhibited serotonin release by other alloantibodies to antigens on the platelet surface. This was shown to be a result of the inhibition of fibrinogen binding to the platelet by bound anti-PlA1.
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology; D016824:Antigens, Human Platelet; D001792:Blood Platelets / Q000276:immunology / Q000378:metabolism*; D005260:Female; D005340:Fibrinogen / Q000378:metabolism; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D066298:In Vitro Techniques; D039661:Integrin beta3; D007518:Isoantibodies / Q000276:immunology*; D007519:Isoantigens / Q000276:immunology*; D010974:Platelet Aggregation; D012701:Serotonin / Q000097:blood*
chemical_list: D000017:ABO Blood-Group System; D016824:Antigens, Human Platelet; D006680:HLA Antigens; C061248:ITGB3 protein, human; D007074:Immunoglobulin G; D039661:Integrin beta3; D007518:Isoantibodies; D007519:Isoantigens; D012701:Serotonin; D005340:Fibrinogen