ABO Blood system: Biosynthesis of Agglutinogenic Alkaline and Non-Agglutinogenic Acid Glycotopes of A and B Antigens at different pH of the culture medium

The biosynthesis of agglutinogenic and adsorbing group A and B glycotopes of erythrocyte's membrane is mediated by the activity of specific glycosyltransferases. The aim of the study – to assess the nature of the biosynthesis of A antigenic glycotopes, depending on pH of the medium during the cultivation of erythrocytes and on antigenic (transferase) characteristics of the donor serum of the other group. Monoclonal antibodies (Mabs) were obtained from IGBRL and under the program IV of the International Workshop on Monoclonal Antibodies and Red Blood Cell Antigens. Biosynthesis was performed with erythrocytes, fresh serum, medium ۱۹۹ and antibiotic solution. Eleven of thirty three samples changed the agglutinogenic characteristics by the end of the cultivation period due to the acquisition of additional agglutinogen corresponding to the donor serum. None of the samples lost their inherent agglutinogen due to its absence in the donor serum. Four of six samples of O (I) erythrocytes acquired the ability to be agglutinated by anti-A reagents, especially strongly by polyclonal anti-A, and the manifestation of agglutination depended on the reaction time. Two of the three samples with initial A(II) agglutinogenic specificity added to the donor serum with Bc'+ characteristic of the erythrocytes acquired this characteristic. However, none of five A(II)Ac'+ samples cultured in the serum of Ac'- O(I)Ac'-Bc'+ and O(I)Ac'-Bc'- donor lost its inherent earlier Ac'+ characteristic. The investigation of inhibitory ability of alkaline and acidic glycoconjugates isolated from membranes revealed, that alkaline Alp-۰۰ and Alp-۱ glycotopes isolated from glycolipids showed the highest inhibitory activity, and the degree of inhibition of polyclonal anti-A antibodies was even higher than that of monovalent BRIC-۱۳۱. The possibility of biosynthesis of non-agglutinogenic specific A and B glycotopes under the influence of a different group serum as a source of the corresponding transferase was shown.

Keywords:

transferase , Erythrocyte , Agglutination , Blood , Detection