title: Clonal diversity of the T-cell population responding to a dominant HLA-A2 epitope of HER-2/neu after active immunization in an ovarian cancer patient.
abstract: Natural antigen processing and presentation of antigen is thought to be important for the generation of a broad functional repertoire of antigen-specific T cells. In this study, the T-cell repertoire to an immunodominant human leukocyte antigen A2 (HLA-A2) binding peptide epitope of HER-2/neu, p369-377, was examined in a patient following immunization with a peptide-based vaccine consisting of helper peptides encompassing HLA-A2 peptide epitopes. The responding T-cell repertoire generated was both phenotypically and functionally diverse. A total of 21 p369-377 clones were generated from this patient. With the exception of two clones, all clones were CD3(+). Sixteen of the clones were CD8(+)/CD4(-). Five of the clones were CD4(+)/CD8(-), despite being generated with an HLA-A2 binding peptide. Nineteen of 21 of clones expressed the alpha beta-T-cell receptor (TCR). The remaining two clones expressed the gamma delta T-cell response (TCR). Selected alpha beta-TCR clones, both CD8(+) and CD4(+), could lyse HLA-A2 transfected HER2 overexpressing tumor cells and p369-377-loaded B-lymphoblastic cell line. In addition to their lytic capabilities these clones could be induced to produce interferon-gamma (IFN-gamma) specifically in response to p369-377 peptide stimulation. The 2 gamma delta-TCR clones expressed CD8 and lysed HLA-A2(+) HER-2/neu(+) tumor cells, but not HLA-A2(-) HER-2/neu(+) tumor cells. One of gamma delta-TCR clones also released IFN-gamma directly in response to p369-377 stimulation. These results suggest that a tumor antigen TCR, directed against a specific epitope, can be markedly polyclonal at multiple levels including CD4/CD8 and TCR.
authors.affiliation: Division of Oncology, Department of Medicine, University of Washington, Seattle, WA 98195-6527, USA. kknutson@u.washington.edu
authors.forename: Keith L
authors.initials: KL
authors.lastname: Knutson
authors.forename: Mary L
authors.initials: ML
authors.lastname: Disis
mesh_terms: D000595:Amino Acid Sequence; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002455:Cell Division; D002461:Cell Line, Transformed; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005260:Female; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D016056:Immunodominant Epitopes / Q000276:immunology*; D007371:Interferon-gamma / Q000096:biosynthesis; D008969:Molecular Sequence Data; D010051:Ovarian Neoplasms / Q000276:immunology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000276:immunology; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000276:immunology; D014611:Vaccination
chemical_list: D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D016056:Immunodominant Epitopes; D007371:Interferon-gamma; D018719:Erb-b2 Receptor Tyrosine Kinases; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta