Analysis of the heterogeneity of the binding site specificities of hyperimmune human anti-A and -A, B sera: the application of competition assays using murine monoclonal antibodies.
Monoclonal antibodies PL41 and AL62 have previously been shown to recognize two distinct blood group A epitopes on the red cell surface. Competitive inhibition of the binding of 125I-PL41 and 125I-AL62 to group A1 red cells, by hyperimmune polyclonal human antibodies, has been employed to investigate the binding site specificities of 15 anti-A and 8 anti-A,B sera. Differences in the degree of inhibition of the binding of the two MABs by individual anti-A or -A,B samples indicate that polyclonal reagents are composed of varying proportions of up to 3 (or more) different antibody specificities, each recognizing a distinct epitope: PL41-like, AL62-like and a third (as yet undefined) category of antibody. In general, those anti-A sera with PL41-like specificities are superior agglutinators of A2B cells with weakly expressed A antigens; similarly, the specificity of potent anti-A,B, sera capable of strongly agglutinating Ax cells was likewise directed towards PL41-binding blood group A trisaccharide haptens.
Lubenko
A
A
North London Blood Transfusion Centre, Colindale, UK.
Savage
J
J
D000017:ABO Blood-Group System / Q000276:immunology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001666:Binding Sites, Antibody; D000939:Epitopes / Q000276:immunology*; D004912:Erythrocytes / Q000276:immunology*; D006801:Humans; D007106:Immune Sera / Q000276:immunology*; D051379:Mice
D000017:ABO Blood-Group System; D000911:Antibodies, Monoclonal; D000939:Epitopes; D007106:Immune Sera