title: HER2/neu-derived peptides recognized by both cellular and humoral immune systems in HLA-A2+ cancer patients.
abstract: HER2/neu is one of the most appropriate target antigens for anti-cancer therapy because of its expression in various types of epithelial cancer. HER2/neu can also be a target for both cellular and humoral immune responses. In this study, we attempted to identify HER2/neu-derived peptides, which are able to be recognized by both humoral and cellular immune systems in HLA-A2+ cancer patients. Among 12 HER2/neu-derived peptides having the HLA-A2 binding motifs, immunoglobulin G reactive to each of 7 HER2/neu peptides was detected in the plasma of >50% of cancer patients. Among these 7 peptides, 3 including HER2/neu 444-452, HER2/neu 466-474, and HER2/neu 484-492, effectively induced peptide-specific and HLA-A2-restricted cytotoxic T lymphocyte activity from peripheral blood mononuclear cells of cancer patients, regardless of different HLA-A2 subtypes. Experiments using blocking antibodies and cold inhibition targets revealed that the cytotoxicity against HER2/neu-expressing HLA-A2+ tumor cells was peptide-specific and CD8+ T cell-dependent. Overall, these results indicate that these 3 HER2/neu-derived peptides are efficiently recognized by both the humoral and cellular immune systems, and therefore could be useful for peptide-based immunotherapy for HLA-A2+ patients with various types of epithelial cancer.
authors.affiliation: Department of Immunology, Kurume University School of Medicine, Kurume 830-0011, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Ishihara
authors.forename: Mamoru
authors.initials: M
authors.lastname: Harada
authors.forename: Koichi
authors.initials: K
authors.lastname: Azuma
authors.forename: Mayumi
authors.initials: M
authors.lastname: Tamura
authors.forename: Hiroki
authors.initials: H
authors.lastname: Shomura
authors.forename: Teruhiko
authors.initials: T
authors.lastname: Fujii
authors.forename: Kyogo
authors.initials: K
authors.lastname: Itoh
authors.forename: Shigeki
authors.initials: S
authors.lastname: Shichijo
mesh_terms: D000917:Antibody Formation; D005260:Female; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D007107:Immune System; D007111:Immunity, Cellular; D007074:Immunoglobulin G / Q000276:immunology; D008297:Male; D009369:Neoplasms / Q000276:immunology*; D009842:Oligopeptides / Q000276:immunology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology* / Q000627:therapeutic use; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D015789:HLA-A2 Antigen; D007074:Immunoglobulin G; D009842:Oligopeptides; D018719:Erb-b2 Receptor Tyrosine Kinases