Biochemical Characterization of a Monoclonal Antibody to the H Type-2 Antigen: Comparison to Other ABH Antibodies

Abstract

Monoclonal and polyclonal antibodies to the ABH blood group antigens were tested for their specificity to glycoproteins with ABH activity on immunoblots of solubilized erythrocyte membranes. Immunoblots were stained with monoclonal antibody G10 to the H type-2 carbohydrate structure or with commercially prepared monoclonal and polyclonal antibodies to A, B, and H blood group antigens. G10 antibody specifically stained antigens in the regions that contain the erythrocyte membrane bands 3 and 4.5; the staining was proportional to the expected H content of the erythrocytes (O > A₂ > B > A₂B > A₁ > A₁B). No specific staining was observed with membranes derived from O_h (Bombay) erythrocytes which lack the H type-2 structure. A commercially prepared monoclonal anti-H did not specifically stain erythrocyte membrane antigens. Monoclonal and polyclonal anti-A specifically stained bands from A and AB but not O, B, or O_h erythrocytes (A₁ > A₁B > A₂ > A₂B). Polyclonal anti-B serum specifically stained bands from B and AB but not O, A, or O_h erythrocytes (B > A₂B > A₁B). However, no specific staining was observed in tests with monoclonal anti-B. Monoclonal antibodies G10 and anti-A and polyclonal anti-A and -B blood typing sera will be useful in the further characterization of the molecular nature of the ABH antigens.