Detection and Characterization of Lewis Antigens in Plasma of Lewis-Negative Individuals

Abstract

Nonacid plasma glycolipids from Lewis-negative individuals of nonsecretor, partial-secretor and secretor phenotypes were prepared and separated by thin- layer chromatography and immunostained with radiolabelled Lewis antibodies. Lewis-positive plasma and intestinal epithelial cell glycolipids from Caucasians representing the four recognized Lewis and secretor combined phenotypes were used as controls. By presenting these purified total glycolipids in a cell-free environment to Lewis antibodies we were able to demonstrate the presence of small amounts of Lewis antigens in Lewis-negative individuals. It is shown that lacto- tetraosylceramide and extended precursor glycolipids are present in all Le(a-b -) nonsecretors. Le^b was detected in 1 of the 3 Le(a-b-) nonsecretor plasmas and in the intestinal sample of the same phenotype. Lactotetraosylceramide was absent but H type 1 and Leb were both present in all group O Le(a-b-) secretors, and extended H typel reactive structures were also found in the partial secretor. These results clearly demonstrate that although the Lewis-negative phenotype exists at the serological level, this phenotype is not an ‘all-or-nothing’ phenomenon at the chemical level. We also show that in the presence of reduced fucosyltransferase activity, increased elongation of the precursor chain occurs, which allows us to postulate that fucosylation of the precursor prevents or at least markedly reduces chain elongation.

Characterization of the Specificities of Human Blood Group H Gene-Specified α1,2-l-Fucosyltransferase toward Sulfated/Sialylated/Fucosylated Acceptors: Evidence for an Inverse Relationship between α1,2-l-Fucosylation of Gal and α1,6-l-Fucosylation of Asparagine-Linked GlcNAc

“…An R1,2-FT in colorectal cancer converted Le a to Le b and Le x to Le y (Yazawa et al 1993). Boland and Deshmukh (1990) found about 50% reduction in mean oligosaccharide chain length in cancerassociated colonic mucins as compared to the mucin isolated from normal colons, and this observation is of interest with the finding of Henry et al (1994) that, in the presence of reduced fucosyltransferase activity, an increased elongation of the precursor carbohydrate chains of glycolipids occurred in Lewis-negative individuals. Recently, the respiratory mucin from cystic fibrosis was shown to contain both sulfation and sialylation of mucin carbohydrate chains carrying blood group H determinant (Lo-Guidice et al, 1994).…”

Variation of human milk oligosaccharides in relation to milk groups and lactational periods

“…Generally, these disaccharide units are either β1,3-linked to one another or to Lac, resulting in elongated linear structures, or β1,6-linked to inner galactose residues, thus building branched oligosaccharides. These core structures are substrates of various fucosyltransferases (FucT) and sialyltransferases in the mammary epithelial cells, and after being modified with fucosyl or sialyl moieties, they probably cannot be elongated or branched anymore ( 9 ) . Carbohydrates containing sialic acids or sulphate groups are classified as acidic oligosaccharides as opposed to the neutral oligosaccharide fraction comprising core structures as well as fucosylated carbohydrates.…”