A short synthetic peptide (DTRPAP) induces anti-mucin (MUC-1) antibody, which is reactive with human ovarian and breast cancer cells.

The present study describes the production of a synthetic hexapeptide (DTRPAP)-based anti-mucin (MUC-1) antibody, similar to those produced using either the intact mucin antigen or tumor extracts. This antibody was generated by immunization of rabbits with the synthetic peptide conjugated to bovine serum albumin as a carrier. Using both the ELISA and FACS analysis methods, we have shown that the antibody is reactive with human ovarian and breast cancer cells, but not with normal epithelial breast cells. This antibody is different from the previously reported anti-mucin HMFG-1, HMFG-2 and SM-3 monoclonal antibodies, since competitive experiments with the free synthetic peptide revealed only a 30% inhibition of HMFG-1 binding to the ovarian (OVCAR-3) cancer cells, as compared to 78% inhibition of the anti-synthetic peptide antibody. The peptide was non-inhibitory for HMFG-2, and induced a significant and reproducible stimulation of the SM-3 binding activity to the tumor cells.