title: Immunochemical studies on blood groups. LI. A comparative study of the reaction of A 1  and A 2  blood group glycoproteins with human anti-A.
abstract: The immunochemical properties of purified A(1) and A(2) glycoproteins have been compared to ascertain whether their antigenic determinants differ. Quantitative precipitin and complement-fixation studies using several anti-A sera as well as purified gammaG anti-A antibodies clearly showed a specificity difference. This was also supported by absorption studies: A(2) substance specifically removed antibodies reacting with A(2) substance leaving anti-A(1) activity. A(1) substance was more effective than A(2) substance in dissolving an A(1) anti-A(1)-specific precipitate. Purified gammaM anti-A hemolyzed A(1) cells more readily than A(2) cells. Inhibition studies using mono- and difucosyl type 2 A-active oligosaccharides showed that type 2 difucosyl receptors are present in A(2) substance. The structural basis for the specificity difference between A(1) and A(2) would appear to be that A(2) substances lack type 1 A determinants; this would account for the observed higher H and Le(b) activity in A(2) substances.
mesh_terms: D000017:ABO Blood-Group System; D000818:Animals; D000906:Antibodies; D000918:Antibody Specificity; D000941:Antigens; D001665:Binding Sites; D003168:Complement Fixation Tests; D000939:Epitopes; D004912:Erythrocytes / Q000276:immunology; D006023:Glycoproteins; D006385:Hemagglutination Inhibition Tests; D006386:Hemagglutination Tests; D006801:Humans; D009844:Oligosaccharides; D013552:Swine
chemical_list: D000017:ABO Blood-Group System; D000906:Antibodies; D000941:Antigens; D000939:Epitopes; D006023:Glycoproteins; D009844:Oligosaccharides