The Origin of ABH Antigens on Human Platelets

• Published in: Blood 1985-03, Vol.65 (3), p.615-619
• Main Authors: Dunstan, Robert A., Simpson, Marcus B., Knowles, Robert W., Rosse, Wendell F.
• Format: Article
• Language: English
• Subjects: ABO Blood-Group System; Absorption; Animals; Antibodies, Anti-Idiotypic; Antibodies, Monoclonal - immunology; Biological and medical sciences; Blood Platelets - immunology; Erythrocytes - immunology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunohematology; Mice - immunology; Platelet immunology
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood.V65.3.615.615

ABH antigens are present on platelets from individuals of the corresponding red cell phenotype, but the extent to which these antigens are intrinsic or adsorbed remains undefined. To evaluate platelets for intrinsic H substance, an IgM mouse monoclonal antibody against type 2H chain (the intrinsic H structure found on erythrocytes) was labeled with 126l and incubated with platelets from donors of different ABO type. The antibody showed dose-response saturation curves, and binding to platelets paralleled that of the red cell ABO type, with 0>B>A1>A1B> Oh cells, giving a single factor variance F of 190 (P < .0005). Passive adsorption of A antigens by platelets has been previously reported. To verify this phenomenon for A and B antigens and to quantitate the elution of A and B antigens from platelets, the following assay system was used. Platelets from group A, and B donors were incubated in plasma from group O donors, and platelets from group O donors were incubated in plasma from different ABO, Lewis, and presumed secretor-type donors. Human IgG anti-A or anti-B was added to the platelets. The amount of antibody bound was determined with a 125l-labeled mouse monoclonal anti-human IgG. When incubated for 96 hours in group O plasma, group A, platelets showed a 45% to 50% decrease in binding of anti-A. There was no significant change in the level of type 2H antigen on these platelets during the same incubation period. Group O platelets incubated in A or B plasmas rapidly acquired the antigens, but if returned to their original plasma, 95% of this passively adsorbed antigen eluted off within 18 hours. The maximum uptake of A and B substances was influenced by the Lewis and secretor type of donor plasma. Our present study demonstrates that ABH antigens on platelets consist of type 2H chains, which are presumably intrinsic as when found on red cells, and of passively adsorbed ABH structures, which are presumably type 1H chains.