Structural and immunochemical identification of Le(a), Le(b), H type 1, and related glycolipids in small intestinal mucosa of a group O Le(a-b-) nonsecretor.
Total nonacid glycosphingolipids were isolated from small intestine mucosal scrapings of a red cell blood group O Le(a-b-) nonsecretor cadaver. Glycolipids were extracted and fractionated into five fractions based on chromatographic and immunostaining properties. These glycolipid fractions were then analysed by thin-layer chromatography for Lewis activity with antibodies reactive to the type 1 precursor (Le(c)), H type 1 (Le(d)), Le(a) and Le(b) epitopes. Fractions were structurally characterized by mass spectrometry (EI-MS and EI-MS/MS-TOF) and proton NMR spectroscopy. EI-MS/MS-TOF allowed for the identification of trace substances in fractions containing several other glycolipid species. Consistent with the red cell phenotype, large amounts of lactotetraosylceramide (Le(c)-4) were detected. Inconsistent with the red cell phenotype, small quantities of Le(a)-5, H-5-1 and Le(b)-6 glycolipids were immunochemically and structurally identified in the small intestine of this individual. By EI-MS/MS-TOF several large glycolipids with 9 and 10 sugar residues were also identified. The extensive carbohydrate chain elongation seen in this individual with a Lewis negative nonsecretor phenotype supports the concept that Lewis and Secretor blood group fucosylation may be a mechanism to control type 1 glycoconjugate chain extension.
Henry
S
S
Department of Clinical Chemistry and Transfusion Medicine, Göteborg University, Sweden.
Jovall
P A
PA
Ghardashkhani
S
S
Elmgren
A
A
Martinsson
T
T
Larson
G
G
Samuelsson
B
B
D000017:ABO Blood-Group System / Q000276:immunology; D000328:Adult; D002240:Carbohydrate Sequence; D005591:Chemical Fractionation; D002855:Chromatography, Thin Layer / Q000379:methods; D006017:Glycolipids / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D006801:Humans; D007413:Intestinal Mucosa / Q000737:chemistry / Q000276:immunology*; D007421:Intestine, Small / Q000276:immunology*; D007983:Lewis Blood Group Antigens / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype
D000017:ABO Blood-Group System; D006017:Glycolipids; D007983:Lewis Blood Group Antigens