Detection of peptide‐specific cytotoxic T‐lymphocyte precursors used for specific immunotherapy of pancreatic cancer

The prognosis of pancreatic cancer is extremely poor with a 5-year survival of approximately 3%. Thus, the development of new treatment modalities, including a specific immunotherapy, is required. Our study investigated whether cytotoxic T-lymphocyte (CTL) precursors reacting to peptides with vaccine candidates (13 peptides for HLA-A2+ or -A24+ patients, respectively) were detectable in the prevaccination peripheral blood mononuclear cells (PBMCs) of 15 pancreatic cancer patients. Peptide-specific CTL precursors were detectable in the majority (11 of 15, 73%) of patients, with a mean positive number of 1.5 peptides (ranging from 0-5 peptides) per patient. Positive peptide profiles varied among patients. These results may provide a scientific basis for a new kind of cancer immunotherapy, namely, a CTL precursor-oriented peptide vaccine, for pancreatic cancer patients.