A Quantitative Study of Le^a, A and H Antigens in Salivas of Australian Caucasians and Aborigines

Abstract

Aboriginal secretors synthesize greater concentrations of H, A and Le^a antigens than do Caucasians but, in A_x secretors, most H determinants are converted to A. Since Aboriginal secretors have concentrations of Le^a in the saliva similar to those of Caucasian non-secretors, it is suggested that the red cell phenotype, Le(a+b+), observed in over 10% of Aborigines, is due to the high concentration of Le^a which is not converted to Le^b. Aboriginal A₁secretors have significantly greater concentrations of Le^a in their salivas than have·secretors. This observation has led to the proposal that, in the genetically-controlled biosynthetic pathways leading to the production of Lewis and ABH antigens in saliva, the genes add their specificities in the order H, A (and/or presumably B), Le.

The Le(a+b+) Phenotype in Polynesians

“…This is not dissimilar to information on Aborigines where Boettcher and Kenny [2] showed that this ethnic group synthesised greater concen trations of Lea and H antigens than Euro peans.…”

“…In adults the Lewis Le(a+b+) pheno type has been previously noted in 11.3% of New Zealand Maoris [1], and in over 10% of Australian Aborigines [2], in one white Australian [3], in Japanese [4,5], 1 % of Chilcotin Indians [6], in a Norwegian [7], a black American [8] and also in some Sibe rians [9]. The absence of the Le(a + b +) phe notype has been reported in many other population groups [9].…”

Genetic and Nongenetic Influences on the ABH and Le^a Antigen Levels of Saliva and Milk

“…This is true for other investigations as well [1][2][3][4]6]. The probable explanation for this fact was advanced by Boettcher [1].…”

Sequence of Action of Genes at the Secretor, H, ABO and Lewis Loci

“…The comparable observation in vitro would be that A or B specilicity is not added to Leh structures, which is the conclusion reached on serological grounds by Boettcher and Kenny [3]. Thus, the biochemical evidence indi cates that the H gene acts before Le for, if it did not, the Leh antigen could not be formed.…”

“…However, since only secretor individuals express the Leh antigen and, at the biochemical level, the Leh antigen is considered to arise where the Lea and I I antigens arc located adjacently on the same oligosaccharide chain, it is apparent that there is interaction, at least at the phenotypic level, between the H and the Lea antigen. Boettcher and Kenny [3] studied H. A and Lea antigens in salivas from australian aborigines, among whom the uncommon red cell phenotype Le(a + b -L) had been found in 13% of the secretors. They found that aborig ines synthesize significantly greater quantities of H and Le11 antigens than Caucasians and.…”