Plasma and Red-Cell Glycolipid Patterns of Le(a+b+) and Le(a+b-) Polynesians as Further Evidence of the Weak Secretor Gene Se^w

Abstract

Monoclonal antibodies and thin-layer chromatography were used to study the unusual erythrocyte Lewis phenotypes found in healthy Polynesians. A single monoclonal anti-Le^b reagent 073 (clone LM129) was found which could detect Le^b antigen on the Polynesian erythrocytes of samples that were unreactive with various polyclonal and monoclonal anti-Le^b reagents. Glycolipid fractions prepared from the plasma and erythrocytes of selected Polynesian samples of red-cell Le(a-b-), Le(a+b-) and Le(a+b+) phenotypes were found to have Le^b glycolipids. The Le^b antigen in some individuals is so weakly expressed that it is undetectable by routine erythrocyte phenotyping. Unusually large glycolipids bearing the Le^b epitope were also found in some Polynesian samples, although the contribution of these novel glycolipids to phenotyping is unclear. The inability to detect Le^b by routine methods and the presence of novel structures can be partially explained in terms of the presence of a weak secretor gene Se^w.

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

“…accumulating over the years to suggest that the Lewis and secretor systems at the phenotypic level in some popula tions, particular Polynesians [7], are more complex than first thought. Further complexities are seen with the differ ential expression of Lewis antigens in different tissues [8,9] and a-4-fucosyltransferase activity in epithelial tissues of red-cell Lewis-negative individuals [10].…”

“…In order to further study the formation of LeJ and Leb antigens and to study the extended Lewis structures found in the plasma of Polynesians [7] we undertook an extensive evaluation of the Lewis glycolipids in Lewis-negative indi viduals. Nonacid glycolipids were prepared from plasma of Lewis-negative Caucasian and Polynesian individuals of nonsecretor and secretor phenotypes, and one sample of the Polynesian partial-secretor phenotype [5,7].…”

“…Nonacid glycolipids were prepared from plasma of Lewis-negative Caucasian and Polynesian individuals of nonsecretor and secretor phenotypes, and one sample of the Polynesian partial-secretor phenotype [5,7]. Lewis-posi tive Caucasian plasma and intestinal epithelial cell glycoli pids from Caucasians representing the four recognized Le wis and secretor combined phenotypes were used as con trols.…”

“…Plasma glycolipids from sample No. 46 (the partial secretor) has been previously studied [7] but additional plasma was obtained for this study. Small-intestinal epithe lial tissue was obtained at autopsy (less than 22 h post mortem) as de scribed [13].…”

“…Total non acid glycolipid fractions were prepared as previously described [15,16]. Erythrocyte and salivary phenotypes were determined using anti sera as previously described [7]. Secretor phenotypes were determined from saliva for the plasma samples and inferred from erythrocyte phe notypes and glycolipid profiles for the cadavers.…”