title: CD4+ Th2 cell recognition of HLA-DR-restricted epitopes derived from CAMEL: a tumor antigen translated in an alternative open reading frame.
abstract: Tumor Ag NY-ESO-1 is an attractive target for immunotherapy of cancer, since both CD8(+) CTL and CD4(+) Th cells against NY-ESO-1 have been described. Moreover, NY-ESO-1 as well as the highly homologous tumor Ag LAGE-1 are broadly expressed in various tumor types. Interestingly, the NY-ESO-1 and LAGE-1 genes also encode for proteins translated in an alternative open reading frame. These alternatively translated NY-ESO-ORF2 and CAMEL proteins, derived from the NY-ESO-1 and LAGE-1 genes, respectively, have been demonstrated to be immunogenic, since CTL specific for these proteins have been isolated from melanoma patients. In this study a panel of advanced melanoma patients was screened for the presence of Th cells specific for the alternatively translated tumor Ags NY-ESO-ORF2 and CAMEL. PBMC of melanoma patients were stimulated for 4 days with mixes of overlapping peptides covering the entire NY-ESO-ORF2 and CAMEL protein sequences and were tested for the release of type 1 (IFN-gamma) and type 2 (IL-13) cytokines in ELISPOT assays. In three of 15 patients, T cells specific for two CAMEL peptides (CAMEL(71-92) and CAMEL(81-102)) could be detected. From one of these patients, CD4(+) T cell clones specific for CAMEL(81-102) could be generated. These clones recognized a naturally processed epitope presented in both HLA-DR11 and HLA-DR12 and produced high levels of IL-4, IL-5, and IL-13. In conclusion, this study shows the presence of Th cells specific for the alternatively translated tumor Ag CAMEL in melanoma patients and is the first report that describes the isolation of tumor Ag-specific CD4(+) Th 2 clones.
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, The Netherlands.
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Slager
authors.forename: Martina
authors.initials: M
authors.lastname: Borghi
authors.forename: Carolien E
authors.initials: CE
authors.lastname: van der Minne
authors.forename: Corlien A
authors.initials: CA
authors.lastname: Aarnoudse
authors.forename: Menzo J E
authors.initials: MJ
authors.lastname: Havenga
authors.forename: Peter I
authors.initials: PI
authors.lastname: Schrier
authors.forename: Susanne
authors.initials: S
authors.lastname: Osanto
authors.forename: Marieke
authors.initials: M
authors.lastname: Griffioen
mesh_terms: D017398:Alternative Splicing / Q000276:immunology*; D000595:Amino Acid Sequence; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D000954:Antigens, Surface; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002461:Cell Line, Transformed; D002469:Cell Separation; D002999:Clone Cells; D004797:Enzyme-Linked Immunosorbent Assay; D018984:Epitopes, T-Lymphocyte / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006684:HLA-DR Antigens / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D018793:Interleukin-13 / Q000096:biosynthesis / Q000378:metabolism; D008545:Melanoma / Q000235:genetics / Q000276:immunology; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000276:immunology*; D014176:Protein Biosynthesis / Q000276:immunology*; D011506:Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D000954:Antigens, Surface; C104948:CTAG1B protein, human; C510162:CTAG2 protein, human; D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D018793:Interleukin-13; D008565:Membrane Proteins; D011506:Proteins; D007371:Interferon-gamma