Антигены АВ0 системы

Обзор литературы посвящен анализу исторических и современных данных о группах крови по системе АВ0. Выстроена логическая цепь с момента открытия групп крови, дальнейшего их исследования до анализа современного состояния вопроса, характеризующегося более детальным изучением генетического обеспечения синтеза, отличительных особенностей строения антигенов А,В и Н, их распространению в природе.

Antigens of AB0 blood group system

The discovery of human blood groups is an important event in medical science development and practice. For the first time, at the end of 1901, the Austrian scientist K. Landsteiner identified three blood groups - A, B and C with the reaction of isohemagglutination. The fourth blood group of ABO system was discovered by A. Decastello and A. Sturli. The priority of digital designation for blood groups (I, II, III, IV) belongs to Y. Jansky, who developed the classification which is widely used all around the world nowadays. In 1910-11 L. Hirzfeld and E. von Dungern demonstrated the ability to inherit AB0 blood groups. In 1924 in England, W. Watkins and W. Morgan found that the antigenic determinants AB0 consist of sugars, namely N-acetylgalactosamine for A-type and galactose for B-antigen. Based on these findings, the Yamamoto group suggested that the alleles A, B and 0 are encoded by glycosyltransferases that transfer N-acetylgalactosamine and galactose, respectively, while, 0 null allele was not able to encode functional glycosyltransferase. In 1995, F. Yamamoto, P. McNeill, S. Hakomori determined the genomic organization of AB0 gene. Numerous studies revealed that antigens AB0 found in primates, in many mammals and vertebrates, plants and some microorganisms are identical to the human ones. The antigens are found both in the membranes of red blood cells, and in endothelial and epithelial cells, they are also expressed on the cells of various organs and tissues (kidneys, heart, skin, bone marrow, liver, etc.). A large number of studies were devoted to the fact that carbohydrates defining group-specific AMS determinants exist in the different molecular forms – glycolipids, glycoproteins and free oligosaccharides. In the 70-80's the abstract science made great achievements in erythrocyte membrane structure examination, and in studies of red blood cell antigen structure and functions.The outer shell of the erythrocyte membrane is a range of large structural proteins (proteins and glycophorin tape), containing complex carbohydrates in the ending. The spaces between erythrocyte membrane outer layer protein structures are filled with lipids. Up to 90% of the determinant antigens A, B, H, and the most part of red blood cells protruding above the surface are localized in the distal part of tape proteins and tape lipids carbohydrate structures. Polysaccharide antigens synthesis proceeded by means of enzymes – A and B-transferases joining a particular sugar residue to the chain precursor. The chain precursor (H-chain antigen) remains untransformed if organism does not synthesize any A-transferase or B-transferase, which corresponds to the blood group 0. The literature data indicates that the membrane surface structures of red blood cells, which are part of red blood cell antigens, serve as a molecular sieve, which holds various protozoan parasites and pathogens, large biologically active molecules, preventing them from entering into the red blood cell and cause hemolysis. Blood group signs are inherited. Glycosyltransferases involved in AB0 blood group antigens synthesis are encoded by allelic genes A, B, 0, located in the q34 locus on chromosome 9. Glycosyltransferase genes are the family of very similar nucleotide sequence, the difference between the A-and B-glycosyltransferase is only 4 amino acids, only two of them, at positions 266 and 268, determine the specificity. Fucosyltransferase (FUT) gene family is located on chromosome 19, H gene (FUT1) gene and Se (FUT2) are this family members. The gene H encodes H-fucosyltransferase. Se gene is expressed in epithelium and encodes another fucosyltransferase.