Characterization of a novel A-active octaglycosylceramide with type 1 chain repeat inherited as a recessive trait in the epithelial cells of the small intestine of inbred rats.

Three strains of inbred rats, AVN, DA and LOU/M, were found to express human blood group A-active glycosphingolipids in the small intestine. Two A phenotypes were detected by immunostaining of thin layer chromatograms with monoclonal anti-blood group A antibody. One phenotype (DA and LOU/M) displayed a novel glycolipid which was characterized as an A-active octaglycosylceramide with a type 1 chain repeat by methylation analysis, electron-impact mass spectrometry of the permethylated and permethylated LiAlH4-reduced molecule, and 1H NMR spectroscopy. It was designated A-8. GalNAc alpha 1-3Gal beta 1-(3GlcNAc beta 1-3Gal beta 1)2-4Glc beta 1-Cer 2 Fuc alpha 1 It is the first description of a type 1 chain repeat in a linear glycolipid. Calculation of minimum energy conformations showed that the orientations of the oligosaccharide chain and A determinant of A-8 differ from those of the homologous structure with a type 2 chain repeat present in human erythrocytes (Hakomori, S., Stellner, K., and Watanabe, K. (1972) Biochem. Biophys. Res. Commun. 49, 1061-1068). Genetic analysis demonstrated that A-8 is inherited as an autosomal recessive trait.