title: Binding of N-acetylgalactosamine-containing compounds by a human IgM paraprotein.
abstract: A serum that contains a monoclonal human IgM paraprotein (McG) agglutinates protease-treated human erythrocytes and binds glycosphingolipids that possess a terminal nonreducing N-acetylgalactosaminyl residue in either the alpha or beta anomeric configuration. The approximately equal reactivity of McG with both anomers of N-acetylgalactosamine was unexpected because most immunoglobulins that bind saccharides exhibit a marked preference for one anomeric configuration. The major receptor for this protein in normal group O erythrocytes is globoside, the blood group P antigen: Ga1NAc( beta, 1 leads to 3)Gal(alpha,1 leads to 4)Gal(b,1 lead to 4)G1c-ceramide. Erythrocytes of the rare Pk and p phenotypes lack globoside, and the former are not agglutinated by McG. The McG receptor in p erythrocytes, which are agglutinated as strongly as normal cells, appears to be a crossreactive glycolipid that contains a much larger number of sugar residues than globoside.
mesh_terms: D000017:ABO Blood-Group System; D000116:Acetylgalactosamine / Q000378:metabolism*; D001666:Binding Sites, Antibody; D004912:Erythrocytes / Q000276:immunology; D005688:Galactosamine / Q000031:analogs & derivatives*; D006027:Glycosides / Q000378:metabolism; D006028:Glycosphingolipids / Q000378:metabolism; D006385:Hemagglutination Inhibition Tests; D006386:Hemagglutination Tests; D006801:Humans; D007075:Immunoglobulin M / Q000378:metabolism*; D066298:In Vitro Techniques; D010127:P Blood-Group System; D010266:Paraproteins / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000494:pharmacology
chemical_list: D000017:ABO Blood-Group System; D006027:Glycosides; D006028:Glycosphingolipids; D007075:Immunoglobulin M; D010127:P Blood-Group System; D010266:Paraproteins; D005688:Galactosamine; D010447:Peptide Hydrolases; D000116:Acetylgalactosamine