Immunochemistry of I/i-active oligo- and polyglycosylceramides from rabbit erythrocyte membranes. Characterization of linear, di-, and triantennary neolactoglycosphingolipids.

H Egge,M Kordowicz,J Peter-Katalinić,P Hanfland

doi:10.1016/s0021-9258(18)89161-x

Abstract

A triantennary ceramide pentadecasaccharide (BIrab-2) with blood group I and B-like activity and an unbranched ceramide heptasaccharide (Birab) with i- and B-like activity were isolated in high yield from rabbit erythrocyte membranes. The structures of the native substances and the products obtained after treatment with alpha-galactosidase (BIrab-2 alpha, Birab alpha) and subsequent Smith degradation (BIrab-2 alpha SD) were determined by sugar analysis, methylation analysis, and fast atom bombardment-mass spectrometry of the permethylated derivatives. Together with the results of 1H NMR analysis (Dabrowski, U., Hanfland, P., Egge, H., Kuhn, S., and Dabrowski, J. (1984) J. Biol. Chem. 259, 7649-7651), the following structures were established for the native substances: (formula; see text) and Gal alpha 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer. Both compounds exhibit strong blood group B-like activity. BIrab-2 alpha is a strong receptor for human anti-I cold agglutinin and Birab for anti-i cold agglutinin.

Highlights

A triantennary ceramide pentadecasaccharide (BIrnb-2)with blood group I and B-like activity and an unbranched ceramide heptasaccharide (Birab)with i- and B-like activity were isolated in high yield from rabbit erythrocyte membranes
The I and i antigens bairoesynthetic precursors of the ABH structure antigens [1,2,3]. They arethe target antigensfor human monoclonal autoantibodies associated with the autoimmune hemolytic anemia known as cold agglutinin disease [4]
I- or i-active glycosphingolipidsfrom bovineand rabbit erythrocytes have been invaluable for the structuraldetermination of I/i antigenicity because they are available in substantial amounts [13,14,15,16,17]

Summary

Methylated sugars

The ion at m / z 709 cannot be attributed to the terminal (GlcNAc)*-Galtrisaccharide because such ions produced by fission of the glycosidic linkage of a hexose are not seen in the FAB spectra of permethylated derivatives of the lacto-N series This ion can be regarded as the lower homologue of the tetrasaccharide fragment m / z 954 where, due to over oxidation, one of the terminal GlcNAc residues was removed.This conclusion is corroborated by the presence of an ion at m / z 1403and apseudomolecular ion at m / z 2508 (Fig.8),all showinga difference of 245mass units ascompared to the fragments from the major component (Scheme 3b). Undegraded shows distinct i activity against several i-antisera, whereas the native ceramide deca- and pentasaccharides reveal I activity, when different I antisera areused [16, 17]

DISCUSSION

Preparatlon of Glycosphlngollplds

Enzymatic Degradation

Smith Degradation

Findings

Hemaqqlutination Inhibition Tests