title: Augmentation of immune response by an analog of the antigenic peptide in a human T-cell clone recognizing mutated Ras-derived peptides.
abstract: T-cells that recognize mutated p21 Ras are relevant to immune surveillance systems against cancer. We report here evidence that immune responses of a T-cell clone recognizing mutated p21 Ras can be augmented by an analog peptide. Using spleen cells from a gastric cancer patient, we established the CD4+ alpha beta Th1-like clone C27 that recognizes wild-type (3EYKLVVVGAGGVGKS17) and mutated p21 Ras protein molecules and peptides, in an HLA-DR1-restricted manner. C27 responded prominently to mutated Ras peptides carrying Val or Ala at position 12, as compared to wild-type and other mutated peptides. C27 also exhibited a much stronger response to a mutated p21 Ras whole-protein molecule-carrying Val at position 12, as compared with the wild-type protein. The proliferative response and production of GM-CSF, TNF-alpha, and IFN-gamma by C27 were further augmented by replacing the possible first DR anchor 4Tyr of the mutated Ras peptide with Trp, a more potent anchor residue for the DR1 molecule. Enhancement of peptide antigenicity by substituting the HLA anchor residue of an antigenic peptide recognized by tumor-reactive T-cells may prove to be a novel strategy for antigen-specific cancer immunotherapy.
authors.affiliation: Department of Neuroscience and Immunology, Kumamoto University Graduate School of Medical Sciences, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yokomizo
authors.forename: S
authors.initials: S
authors.lastname: Matsushita
authors.forename: S
authors.initials: S
authors.lastname: Fujisao
authors.forename: S
authors.initials: S
authors.lastname: Murakami
authors.forename: H
authors.initials: H
authors.lastname: Fujita
authors.forename: M
authors.initials: M
authors.lastname: Shirouzu
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
authors.forename: M
authors.initials: M
authors.lastname: Ogawa
authors.forename: Y
authors.initials: Y
authors.lastname: Nishimura
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000595:Amino Acid Sequence; D019138:Antibodies, Blocking / Q000494:pharmacology; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000941:Antigens / Q000494:pharmacology*; D002999:Clone Cells; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010446:Peptide Fragments / Q000276:immunology* / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*; D018631:ras Proteins / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D019138:Antibodies, Blocking; D000911:Antibodies, Monoclonal; D000941:Antigens; D010446:Peptide Fragments; D018631:ras Proteins