Polypeptide core of a human pancreatic tumor mucin antigen.

This work describes the molecular properties of the polypeptide core of a human pancreatic mucin antigen isolated from a human pancreatic adenocarcinoma cell line, HPAF. Pancreatic tumor mucin was isolated by a combination of molecular sieve chromatography and CsCl/4 M guanidine-HCl density gradient ultracentrifugation. Trifluoromethane sulfonic acid was used to remove carbohydrate units from purified mucin molecules. A rabbit monospecific polyclonal antibody was generated against pancreatic apomucin and reacted with a Mr greater than 200,000 species. The antibody binding data indicated that the rabbit antiserum raised against pancreatic apomucin cross-reacted with a breast mucin synthetic peptide. Northern blot and immunodot blot analyses of various cell line extracts revealed that a tandem repeat sequence and a similar mRNA were detected in both pancreatic and breast mucin-producing cell lines. These results suggest that pancreatic apomucin and breast apomucin share some similarity in tandem repeated nucleic acid and protein sequences.