Production of three monoclonal antibodies specifically reactive respectively with the ductal, acinar and islet cells of the human pancreas.

Three monoclonal antibodies, designated FP-1, FP-2 and FP-3, were obtained by immunizing a BALB/c mouse with dispersed human fetal pancreatic cells and using hybridoma technology. FP-1, FP-2 and FP-3 reacted specifically, respectively, with the ductal epithelial, acinar and islet cells, of the fetal pancreas as well as with adult human pancreatic tissue, suggesting a use in the discrimination of pancreatic cell types. Upon screening various tumor tissues, FP-1 was found to react with adenocarcinomas of the pancreas (16/23), stomach (7/8), colon (4/6) and gall bladder (2/2) as well as with the three malignant cell lines, PANC-1 (pancreas), HT-29 (colon) and LoVo (colon). In contrast to FP-1, FP-2 and FP-3 reacted with only 5% (2/39) and 0% (0/39), respectively, of these adenocarcinomas. Although FP-3 did not react with any of these adenocarcinomas, it did react with various APUDoma cells such as islet cell tumors of the pancreas (3/5), pheochromocytomas (2/2), medullary thyroid carcinomas (2/3) and gastrointestinal carcinoids (1/3). FP-3 thus appears to be the first monoclonal antibody with extremely high endocrine cell specificity.