In vitro fixation of C3d and C5b-9 on platelets by human platelet reactive antibodies.
Most platelet-reactive autoantibodies and alloantibodies are not able to fix complement in vitro. However, exceptions have been found. These antibodies are usually characterized by the conventional platelet complement fixation test. A recently developed competitive enzyme immunoassay for quantitation of platelet-associated immunoglobulins and a modification thereof allowed the quantitative study of fixation of C3d and the membrane attack complex (C5b-9) on platelets by HLA antibodies, human platelet autoantibodies, and drug-dependent antibodies (ddab). The highest amounts of both complement products were fixed through ddabs, whereas autoantibodies only showed moderate complement fixation. This enzyme immunoassay is a valuable tool for the characterization of the complement-fixing properties of platelet-reactive antibodies.
Kiefel
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V
Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig-University, Giessen, Federal Republic of Germany.
Salama
A
A
Mueller-Eckhardt
C
C
D000906:Antibodies / Q000502:physiology*; D000937:Antigen-Antibody Reactions; D000961:Antilymphocyte Serum / Q000502:physiology; D001323:Autoantibodies / Q000502:physiology; D001792:Blood Platelets / Q000276:immunology / Q000378:metabolism*; D003176:Complement C3 / Q000378:metabolism*; D015933:Complement C3d; D003168:Complement Fixation Tests; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000378:metabolism*; D005260:Female; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000502:physiology; D007075:Immunoglobulin M / Q000502:physiology; D008297:Male; D004364:Pharmaceutical Preparations
D000906:Antibodies; D000961:Antilymphocyte Serum; D001323:Autoantibodies; D003176:Complement C3; D015938:Complement Membrane Attack Complex; D006680:HLA Antigens; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D004364:Pharmaceutical Preparations; D015933:Complement C3d; D003165:Complement System Proteins