title: HLA-A3 restricted mutant ras specific cytotoxic T-lymphocytes induced by vaccination with T-helper epitopes.
abstract: Cytotoxic T-lymphocytes are one of the most important elements of the antitumor defense. Stimulation of cytotoxic T-lymphocytes outgrowth after immunization with mutant ras peptides is a desired goal since these cells may kill tumor cells in vivo. In this study we tested responding peripheral mononuclear cells from a patient with pancreatic adenocarcinoma who had received intradermal peptide vaccination with a mixture of 17-mer mutant ras peptides and granulocyte-macrophage colony-stimulating factor as an adjuvant. Responding peripheral T-cells were cloned by limiting dilution and several CD8(+) cytotoxic T-lymphocytes, specific for the K- RAS 12-Cys mutation were obtained. By using a panel of nonamer peptides containing the 12-Cys mutation and covering position 4-21 in the ras molecule, the 9-mer peptide which was actually recognized by the cytotoxic T-lymphocytes could be identified. HLA-A*0302 could be identified as the antigen-presenting molecule, and the amino acid sequence of the T-cell epitope carries the previously identified HLA-A*0302 binding motif. The nonamer peptide was contained within the vaccine peptide originally used for intradermal immunization of the patient. The cytotoxic T-lymphocytes were capable of killing target cells expressing HLA-A*0302 that coexpressed the K- RAS 12-Cys mutation after transfection. These data demonstrate that the peptide used for vaccination (17-mer) is processed and presented in vivo, and that generation of cytotoxic T-lymphocytes by vaccination with T-helper epitopes may be important for further development of specific immunotherapy of cancer patients.
authors.affiliation: Section for Immunotherapy, Department of Immunology, Norwegian Radium Hospital, University of Oslo, Montebello, 0310 Oslo, Norway. m.k.gjertsen@labmed.uio.no
authors.forename: Marianne Klemp
authors.initials: MK
authors.lastname: Gjertsen
authors.forename: Ingvil
authors.initials: I
authors.lastname: Saeterdal
authors.forename: Stein
authors.initials: S
authors.lastname: Saebøe-Larssen
authors.forename: Gustav
authors.initials: G
authors.lastname: Gaudernack
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology; D000328:Adult; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000276:immunology; D019496:Cancer Vaccines / Q000276:immunology / Q000627:therapeutic use*; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D005260:Female; D011905:Genes, ras; D015791:HLA-A3 Antigen / Q000276:immunology*; D006801:Humans; D009154:Mutation; D010190:Pancreatic Neoplasms / Q000235:genetics / Q000276:immunology / Q000628:therapy; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology / Q000627:therapeutic use; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D016896:Treatment Outcome; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000276:immunology / Q000627:therapeutic use*
chemical_list: D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D000939:Epitopes; D015791:HLA-A3 Antigen; D010446:Peptide Fragments; D014614:Vaccines, Synthetic; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras)