Analysis of monoclonal antibodies for identification of antigens associated with tumours of the gastrointestinal tract.

The reactivity of a new anti-human gastric carcinoma antibody, GL-013 with gastrointestinal tissue sections, with subcellular membranes (both from normal and malignant specimens), and with a variety of purified tumour antigens, has been evaluated and compared with that of a panel of monoclonal antibodies. These include antibodies against carcinoembryonic antigen (CEA), normal cross reacting antigen (NCA) and the Y-hapten. The reactivity of GL-013 antibody was distinct from, but not superior to that of the existing reagents. Of these, the antibody against the Y hapten was the most discriminatory with respect to its preferential reactivity with tumours, and the target tetrasaccharide comprising the Y hapten determinant was identified upon a variety of cellular macromolecules, including glycoproteins, glycolipids and on epidermal growth factor receptors. This is in accord with its frequent association with tumours.