The blood group B type-4 heptaglycosylceramide is a minor blood group B structure in human B kidneys in contrast to the corresponding A type-4 compound in A kidneys. Structural and in vitro biosynthetic studies.
Blood group A glycolipid antigens have been found based upon at least four different core saccharides (types 1 to 4). The biological significance of this structural polymorphism is not known, although the successful outcome of transplantations of blood group A2 kidneys to blood group O individuals have been partly explained by the low expression of A type-3 and -4 chain glycolipid antigens in A2 kidneys. If graft rejection due to ABO incompatibility is, in any way, correlated to the expression of type-3 and -4 chain blood group glycolipids, it is of interest to identify possible blood group B structures based on these core saccharides. In a non-acid glycosphingolipid fraction isolated from human blood group B kidneys, mass spectrometry, high-temperature gas chromatography-mass spectrometry and probing of thin-layer chromatograms with Gal alpha 1-4Gal-specific Escherichia coli and monoclonal anti-B antibodies provided evidence for minute amounts of a Gal alpha 1-3(Fuc alpha 1-2)Gal beta-HexNAc-Gal alpha 1-4Gal beta-Hex-Ceramide structure consistent with a B type-4 chain heptaglycosylceramide. In contrast, blood group A kidneys have the corresponding A type-4 chain heptaglycosylceramide as the predominant blood group A glycolipid. No, or very low activity of the blood group B gene enzyme on the type-4 chain blood group H hexaglycosylceramide precursor was found by biosynthetic experiments in vitro, which might explain the low expression of type-4 chain blood group B heptaglycosylceramides in human blood group B kidneys.
Holgersson
J
J
Department of Medical Biochemistry, University of Göteborg, Sweden.
Bäcker
A E
AE
Breimer
M E
ME
Gustavsson
M L
ML
Jovall
P A
PA
Karlsson
H
H
Pimlott
W
W
Samuelsson
B E
BE
D000017:ABO Blood-Group System; D000941:Antigens / Q000276:immunology; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002518:Ceramides / Q000032:analysis / Q000737:chemistry* / Q000276:immunology; D002855:Chromatography, Thin Layer; D008401:Gas Chromatography-Mass Spectrometry; D006017:Glycolipids / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D006801:Humans; D007668:Kidney / Q000737:chemistry / Q000276:immunology*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data
D000017:ABO Blood-Group System; D000941:Antigens; D002518:Ceramides; D006017:Glycolipids