Immunochemistry of O-glycosidically-linked Gal(beta 1 leads to 3) GalNAc on fragments of human glycophorin A

N-terminal and internal fragments of human glycophorin A with chemically defined carbohydrate moieties have been used as immunogens after conjugation to BSA or polymerization to produce carbohydrate-directed antibodies with the desired specificity against O-glycosidically linked D-galactopyranosyl-beta-(1 leads to 3)-N-acetyl-D-galactopyranosamine, a possible marker on transformed T-lymphocytes and mammary tissue of humans. Antisera from rabbits have been characterized by inhibition studies using 125I-labelled peptides in radioimmunoassay and by haemagglutination inhibition. The inhibition caused by natural and synthetic glycoconjugates, which have no structural correspondence with the antigen except its carbohydrates, clearly indicated the formation of antibodies specific for Gal-beta(1 leads to 3)-GalNAc in serum A3.