Eligibility of antigenic-peptide-pre-loaded and fixed adhesive peripheral blood cells for induction of cytotoxic T lymphocytes from cancer patients with elevated serum levels of carcinoembryonic antigen

The inducibility of cytotoxic T lymphocytes (CTL) that react with carcinoem bryonic antigen (CEA) was tested in cancer patients with elevated (more tha n 5 ng/ml) serum CEA levels when antigen presentation was carried out with paraformaldehyde-fixed adhesive peripheral blood mononuclear cells (PBMC) f rom the patient that had been pre-loaded with CEA652(9), an HLA-A2402-reres trtcd tumor antigenic peptide derived from CEA. By culturing fresh autologo us PBMC on the fixed cell layer in medium containing interleukin-1, -2, -4 and -6. three out of eight patients developed CTL. The CTL from two of thes e patients killed CEA-protein-producing gastric cancer cells carrying HLA-A 2402 and the cells from the remaining patient killed CEA-non-producing stom ach cancer cells pre-loaded with CEA652(9). The results suggest that a sing le antigenic peptide on the fixed adhesive cells will allow the ex vivo ind uction of peptide-reactive CTL that are easier to handle and allow antigen presentation without tedious preculture of the "professional" antigen-prese nting dendritic-cells.