The histo-blood group ABH determinants are major allogeneic antigens in both erythrocytes and tissues of humans. They generally constitute peripheral parts of the oligosaccharide chains of glycoconjugates, i.e., linked to lipids (glycosphingolipids) or to proteins (glycoproteins). The structure of the antigen determinants was established in the 1950s by Watkins and Morgan (Nature 180:1038-1040, 1957) and Kabat et al. (Blood Group Substrates: Their Chemistry and Immunochemistry. 1956, Academics Press, New York). Subsequently, Watkins and Morgan (Vox Sang. 4:97-119, 1959) proposed that the A and B phenotypes were associated with glycosyltransferases that converted the H substance associated with 0 phenotype to A and B, respectively, through the addition of .alpha.1.fwdarw.3-N-acetylgalactosamine or .alpha.1.fwdarw.3-galactosyl residues to H antigen, Fuc.alpha.1.fwdarw.2Gal.beta.1.fwdarw.R. Thus, the primary products of the histo-blood group A and B genes are the respective glycosyltransferases.
At present, knowledge of the histo-blood group antigens is limited to their chemistry, immunology, biosynthesis and genetic inheritance. DNA sequence information for the ABO genes has not been available, due primarily to the difficulty associated with purifying mammalian glycosyltransferases in sufficient quantities. Nucleotide probes based on amino acid sequence information of the A and B transferase proteins would allow cloning and characterization of the ABO genes, and thereby permit methods for direct DNA blood grouping.
Consequently, there exists a need in the art for purified histo-blood group A or B glycosyltransferase and the primary structure of the genes encoding them. The present invention fills this need, and further provides other related advantages.