A monoclonal antibody that recognizes a cluster of a disaccharide, NeuAc alpha(2—-6)GalNAc, in mucin-type glycoproteins.

The structure of an epitopic carbohydrate recognized by a monoclonal antibody, MLS 102, was determined. A disaccharide, NeuAc alpha (2----6)GalNAc, the major prosthetic group of ovine submaxillary mucin (OSM) and related synthetic glycosides, NeuAc alpha(2----6)GalNAc alpha----Ser, NeuAc alpha(2----6)GalNAc beta----Ser, and NeuAc alpha (2----6)GalNAc beta----propyl, reacted with MLS 102 to similar extents, but the reaction was considerably weaker compared to that of OSM. This difference in reactivity could be ascribed to the occurrence of a cluster of the disaccharide on OSM. Purification of MLS 102-reactive antigens from a Triton X-100 extract of LS 180 cells by means of immunoaffinity chromatography gave mucin fractions (cMLS 102 antigen) with an OSM-like domain. Correlation between the content of the disaccharide, NeuAc alpha(2----6)GalNAc, in mucins and their reactivity with MLS 102 was observed.