Human pancreatic cancer-associated antigens detected by murine monoclonal antibodies.

Two monoclonal antibodies, YPan1 and YPan2, were produced from spleen cells of mice immunized against a human pancreatic cancer cell line, Capan-2, which also reacted with eight other human pancreatic carcinoma cell lines and with sections of cancerous human pancreas tissue. Reactivity was also found with colonic and stomach carcinoma tissues. Whereas YPan1 reacted strongly with normal pancreatic tissue, it bound weakly, if at all, to a variety of other normal tissues. YPan1 reacted with both the membranes and cytoplasm of pancreatic adenocarcinoma cells and with constituents of normal pancreatic ductal cells and duct luminal contents. YPan2, on the other hand, reacts to a greater degree with intracytoplasmic constituents in pancreatic adenocarcinoma cells. Unlike YPan1, YPan2 reacted weakly with only one of 16 cases of normal pancreas. Pretreatment of the tissue with neuraminidase abolished YPan1's reactivity, which indicated that sialic acid may be involved in the antigenic activity of the molecule(s) recognized by YPan1. Neuraminidase pretreatment had no effect on YPan2 reactivity. Neither YPan1 nor YPan2 competed with 19-9 monoclonal antibody in binding to soluble CA 19-9 antigen. These results suggest that these monoclonal antibodies are of potential use in the diagnosis of pancreatic carcinoma.