ABO blood group determinants with branched cores.

Abstract

ALTHOUGH the biochemical basis of ABO and Lewis blood types in man has on the whole been elucidated1, more detailed information is needed about the carbohydrate structures of the A and B subgroups2. But investigation has been limited by the complexity of the sugar chains of these antigens3. Information can, however, be obtained from the study of human milk oligosaccharides, which are synthesised by a series of glycosyl transferases which mediate the formation of glycoproteins, especially those of blood group substances1. Our studies have shown that, contrary to the composite structures of ABO and Lewis blood group determinants described by Lloyd and Kabat3 (Fig. 1), the H determinant is located only on the type 1 carbohydrate chain (Galβ1→GlcNAc....) of the branched sugar grouping.