title: Identification of multiple HLA-DR-restricted epitopes of the tumor-associated antigen CAMEL by CD4+ Th1/Th2 lymphocytes.
abstract: CD4(+) Th cells play an important role in the induction and maintenance of adequate CD8(+) T cell-mediated antitumor responses. Therefore, identification of MHC class II-restricted tumor antigenic epitopes is of major importance for the development of effective immunotherapies with synthetic peptides. CAMEL and NY-ESO-ORF2 are tumor Ags translated in an alternative open reading frame from the highly homologous LAGE-1 and NY-ESO-1 genes, respectively. In this study, we investigated whether CD4(+) T cell responses could be induced in vitro by autologous, mature dendritic cells pulsed with recombinant CAMEL protein. The data show efficient induction of CAMEL-specific CD4(+) T cells with mixed Th1/Th2 phenotype in two healthy donors. Isolation of CD4(+) T cell clones from the T cell cultures of both donors led to the identification of four naturally processed HLA-DR-binding CAMEL epitopes: CAMEL(1-20), CAMEL(14-33), CAMEL(46-65), and CAMEL(81-102). Two peptides (CAMEL(1-20) and CAMEL(14-33)) also contain previously identified HLA class I-binding CD8(+) T cell epitopes shared by CAMEL and NY-ESO-ORF2 and are therefore interesting tools to explore for immunotherapy. Furthermore, two CD4(+) T cell clones that recognized the CAMEL(14-33) peptide with similar affinities were shown to differ in recognition of tumor cells. These CD4(+) T cell clones recognized the same minimal epitope and expressed similar levels of adhesion, costimulatory, and inhibitory molecules. TCR analysis demonstrated that these clones expressed identical TCR beta-chains, but different complementarity-determining region 3 loops of the TCR alpha-chains. Introduction of the TCRs into proper recipient cells should reveal whether the different complementarity-determining region 3 alpha loops are important for tumor cell recognition.
authors.affiliation: Department of Clinical Oncology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Elisabeth H
authors.initials: EH
authors.lastname: Slager
authors.forename: Caroline E
authors.initials: CE
authors.lastname: van der Minne
authors.forename: Margreet
authors.initials: M
authors.lastname: Krüse
authors.forename: Dilja D
authors.initials: DD
authors.lastname: Krueger
authors.forename: Marieke
authors.initials: M
authors.lastname: Griffioen
authors.forename: Susanne
authors.initials: S
authors.lastname: Osanto
mesh_terms: D000595:Amino Acid Sequence; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D000954:Antigens, Surface; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D002999:Clone Cells; D018984:Epitopes, T-Lymphocyte / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D006684:HLA-DR Antigens / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology; D008545:Melanoma / Q000276:immunology / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D011994:Recombinant Proteins / Q000276:immunology / Q000378:metabolism; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism*; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism*
chemical_list: D000951:Antigens, Neoplasm; D000954:Antigens, Surface; C104948:CTAG1B protein, human; C510162:CTAG2 protein, human; D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D008565:Membrane Proteins; D010446:Peptide Fragments; D011994:Recombinant Proteins