A monoclonal anti-glycophorin A antibody recognizing the blood group M determinant: studies on the subspecificity.
A mouse monoclonal antibody (425/2B, IgM) was obtained which shows specificity for blood group M determinant of glycophorin A. The antibody is pH-dependent. At pH 6-7 it reacted strongly with blood group M antigen, but also cross-reacted distinctly with N antigen. At pH 8.3 the antibody showed moderately decreased reactivity with M antigen, but no interaction with N antigen was detectable by hemagglutination, immunoblotting, or microplate ELISA. The direct binding studies and inhibition of 425/B antibody by untreated or modified blood group M and N glycoproteins or tryptic glycopeptides showed that the binding to the antigens was not affected by acetylation of their amino groups, or removal of amino-terminal amino acid residue. Desialylation of the antigens decreased their reactivity with the antibody and this effect was distinctly stronger at pH 7 than 8.3. The antibody reacted strongly at pH 7 and 8.3 with glycophorin B of Henshaw phenotype, whereas its reactivity with normal glycophorin B was weak or undetectable at these pH values, respectively. The results obtained indicated that anti-M specificity of 425/2B antibody is related to the 5th amino acid residue of glycophorin A (anti-Mgly specificity) and that pH shift from 7 to 8.3 changes the fine specificity of the antibody. At pH 8.3 the reactivity of the antibody is more dependent on glycine residue (higher anti-M specificity) and less dependent on sialic acid residues in the antigen.
D000818:Animals; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000032:analysis*; D006020:Glycopeptides / Q000276:immunology; D006021:Glycophorins / Q000276:immunology*; D006023:Glycoproteins / Q000276:immunology; D006384:Hemagglutination; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007519:Isoantigens / Q000032:analysis; D008951:MNSs Blood-Group System / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D012795:Sialoglycoproteins / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D006020:Glycopeptides; D006021:Glycophorins; D006023:Glycoproteins; D007519:Isoantigens; D008951:MNSs Blood-Group System; D012795:Sialoglycoproteins