Abstract

A new monoclonal antibody has been developed which is capable of detecting structures in gastric mucus glycoproteins expressed in the fetus and in adult gastric mucosa in conditions such as gastric carcinoma. Cancer associated monoclonal antibodies were selected by testing them against various mucous glycoprotein samples from the alimentary tract, including salivary glycoproteins from both secretory and non-secretory subjects, and cancerous and normal gastric juice glycoproteins. They were tested against 1000 samples of gastric juice from an unselected population. Immunochemical characterisation suggested that the glycoproteins picked up by P4 and i11 include one of the compounds reacting with rabbit anti-fetal sulphoglycoprotein antigen serum. On the basis of a clinical trial and immunohistological evaluation further evidence was obtained of P4 as the most promising antibody for further experimentation. A total of 302 gastric juice specimens from patients with various gastric symptoms were analysed using the enzyme linked immunosorbent assay technique and P4 antibody. Of 10 gastric cancers, nine had P4 in the gastric juice. A positive correlation was found between gastric ulcer and the appearance of P4. Duodenal ulcers were not correlated to P4. Atrophic gastritis and P4 coincided less frequently. Raised P4 values were found in between 3% and 9% of subjects, depending on the population. Cancer cases showed high P4 values, which allows adjustment of the lower limit of a positive result to high level whereby a considerable number of non-cancerous P4 positives are omitted.