Immunoaffinity Isolation of a Sialyl-Lea Oligosaccharide from Human Milk1

A cancer-associated antigen, sialyl-Le(a) oligosaccharide, was isolated from human milk using a monoclonal antibody recognizing carbohydrate moieties of mucin-type glycoproteins. The structure was identified as: (Formula: see text) based on 500-MHz 1H-NMR spectroscopy. This oligosaccharide comprises 0.07% of sialyloligosaccharides in human milk. The NMR spectra of two fellow oligosaccharides, Le(a) oligosaccharide (or lacto-N-fucopentaose II) and LS-tetrasaccharide a, are also given.