[Interaction between normal A1 or A2 and B alleles in the AB heterozygote. Comparative study of European and African families]. / Interaction entre allèles normaux A1 ou A2 et B chez l'hétérozygote AB: Etude comparative portant sur des familles européennes et africaines.

A comparative study of European and African families is described to demonstrate interaction between A1 and A1B, A2 and A2B, B and A1B, B and A2B phenotypes who have either the same A allele or the same B allele. The quantitation of the agglutination has been determined by the "agglutination percentage measurement". The following reagents were used: human anti-A and anti-B, anti-A1 extracted from Dolichos biflorus and anti-H serum extracted from Ulex europaeus. In the A1 and A1B families--who received the same A1 allele--a weaker agglutination by anti-A1 and anti-A is observed in A1B Africans. In the A2 and A2B families who received the same A2 allele, the agglutination with anti-A is depressed from A2 to A2B in the European and African populations. In the B and A1B families who received the same B allele, a weakened agglutination between B and A1B with anti-B is only observed for the A1B Europeans. In the B and A2B families who received the same B allele, there is no variation of the agglutination between B and A2B with anti-B. The H status is the same for European and African populations, although the B Africans had less H but more B than Europeans. The results of our study led to the observation that the Africans have H deficient or a strong B gene. Like SSEBABI, we think that a strong B gene is perhaps acting more intensely on H substrate than A1.

[Relationship between the quantities of H substance before, and B substance after conversion of red blood cells by alpha-D-galactosyl transferase]. / Relation entre quantité de substance H avant transformation, et quantité de substance B aprés transformation de globules rouges O par L'alpah-D-galactosyl transférase.

The authors determined the agglutination percentages with anti-B, eel and Ulex europeus anti-H reagents for the kinetic study of the in vitro conversion O red blood cells in B. The agglutination with the anti-B increases in proportion as the agglutination with eel anti-H decreases; the agglutination with Ulex anti-H remains constant. They converted (time=18 h) O red blood cells with a more or less high substance H content (adults in good health, africans and europeans, patients, newborn and one "Bombay" phenotype). They showed that there is a good correlation between the agglutination percentages with eel anti-H or Ulex anti-H before conversion and the agglutination percentages with anti-B after conversion. These "O converted" look like the B phenotype defined by a check sample of B subjects.

[Some aspects of the allelic interaction in family studies of normal A1B and A2B subjects (author's transl)]. / Quelques aspects de l'interaction allélique à l'aide d'études familiales de A1B et A2B normaux.

The authors have selected three series of families presenting several heterozygous AB gene combinations: the same gene A and the same gene B; the same gene B and different genes A; and the same gene A and different genes B. The results concerning these families show that the quantitiy of A1 and A substances (for A1B) or A (for A2B) is related to the "quality" of the alpha-D-galactosyl transferase acting on a more or less important H substratum. The alpha-N-acetyl-D-galactosaminyl transferase seems to have a minor function.