The human blood groups (ABO) are known to be determined by the terminal carbohydrate residues attached to common carbohydrate chains of the red cell surface. Specific transferases, i.e., N-acetylgalactosaminyltransferase (A enzyme) in blood group A persons and galactosyltransferase (B enzyme) in blood group B persons, are responsible for transferring the carbohydrates to the terminal galactose of the H-substance of the O red cell surface, with both enzymes absent in blood group O persons. It has not been clear whether the expression of these transferases is related to allelic structural genes or is under regulatory control. The activities of A and B enzymes were completely neutralized by the anti-A-enzyme antibody, which was obtained from a rabbit immunized with purified A enzyme. When pretreated with a protein component obtained from blood group O plasma, the antibody had no capacity for neutralization of the two enzymes. If the transferases are under regulatory control, no immunologically cross-reactive protein should be produced in blood type O persons. The existence of an immunologically active component in blood group O plasma proves that the genes for A enzyme, B enzyme, and the immunologically cross-reactive protein in O plasma are allelic and excludes the possibility of involvement of regulatory control in blood group expression.
CITATION STYLE
Yoshida, A., Yamaguchi, Y. F., & Dave, V. (1979). Immunologic homology of human blood group glycosyltransferases and genetic background of blood group (ABO) determination. Blood, 54(2), 344–350. https://doi.org/10.1182/blood.v54.2.344.bloodjournal542344
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