title: 707-AP peptide recognized by human antibody induces human leukocyte antigen A2-restricted cytotoxic T lymphocyte killing of melanoma.
abstract: We recently identified a tumor-associated antigen that was recognized by human monoclonal antibody L94. The antibody-reactive 707-AP sequence RVAALARDAP, cloned from a melanoma cDNA library, was also found to be recognized by peripheral blood lymphocytes (PBLs) from melanoma patients. In this study, 707-AP was used to stimulate melanoma patients' PBLs for the establishment of peptide-specific CTL cell lines. CTL cell lines derived from 258 melanoma patients of different human leukocyte antigen (HLA)-A and HLA-B allele expressions were assessed by a 51Cr cytotoxicity assay against the peptide-pulsed autologous B lymphoblastoid cells and T2 HLA-A2 antigen-presenting cells and autologous and allogeneic melanoma cell lines. The analysis of 707-AP CTL activity demonstrated that only HLA-A2 patients' PBLs could be stimulated with 707-AP. 707-AP CTLs were able to specifically lyse HLA-A2 autologous and allogeneic melanoma cell lines. This verified the endogenous processing and presentation of 707-AP by melanoma cells. 707-AP CTL cytotoxicity against peptide-pulsed autologous HLA-A2 B lymphoblastoid cells and T2 HLA-A2 cells was also demonstrated. The killing activity of HLA-A2 707-AP CTL cell lines (CD8+ CD3+) was inhibited by anti-HLA class and anti-HLA-A2 monoclonal antibodies. The amino acid substitution or deletion analysis of the 707-AP sequence in CTL stimulation and recognition confirmed that position 2, amino acid V and position 9, amino acid A were essential. Both positions are known as supermotif anchors for HLA-A2 peptide sequences. Our studies demonstrated that 707-AP is a potent stimulator of CTLs that can induce peptide-specific HLA-A2 melanoma cell killing. The recognition of 707-AP by both antibody and CTLs suggests its potential significance as a peptide immunotherapeutic.
authors.affiliation: Departments of Biotechnology Sciences, John Wayne Institute for Cancer Treatment and Research, Santa Monica, California 90404, USA.
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: R F
authors.initials: RF
authors.lastname: Irie
authors.forename: Y
authors.initials: Y
authors.lastname: Nishinaka
authors.forename: D S
authors.initials: DS
authors.lastname: Hoon
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D003602:Cytotoxicity, Immunologic; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology*; D013329:Structure-Activity Relationship; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000911:Antibodies, Monoclonal; D015789:HLA-A2 Antigen; D009842:Oligopeptides