Natural CD8+ T-cell responses against MHC class I epitopes of the HER-2/neu oncoprotein in patients with epithelial tumors |
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Authors: | Panagiota?A.?Sotiropoulou,Sonia?A.?Perez,Volfgang?Voelter,Hartmut?Echner,Ioannis?Missitzis,Nick?B.?Tsavaris,Michael?Papamichail,Constantin?N.?Baxevanis author-information" > author-information__contact u-icon-before" > mailto:cacenter@otenet.gr" title=" cacenter@otenet.gr" itemprop=" email" data-track=" click" data-track-action=" Email author" data-track-label=" " >Email author |
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Affiliation: | (1) Cancer Immunology and Immunotherapy Center, Saint Savas Cancer Hospital, 171 Alexandras Avenue, 115 22 Athens, Greece;(2) Abteilung Fuer Physicalische Biochemie des Physiologisch-Chemisches Institut der Universitaet, 4 Hoppe-Seyler Strasse, 72076 Tuebingen, Germany;(3) Breast Cancer Clinic, Saint Savas Cancer Hospital, 171 Alexandras Avenue, 115 22 Athens, Greece;(4) Department of Pathophysiology, University of Athens, School of Medicine, Laikon General Hospital, Greece |
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Abstract: | HER-2/neu is an immunogenic protein eliciting both humoral and cellular immune responses in patients with HER-2/neu-positive (+) tumors. Preexisting cytotoxic T lymphocyte (CTL) immunity to HER-2/neu has so far been mainly evaluated in terms of detection of CTL precursor (CTLp) frequencies to the immunogenic HLA-A2–binding nona-peptide 369-377 (HER-2(9369)). In the present study, we examined patients with HER-2/neu+ breast, ovarian, lung, colorectal, and prostate cancers for preexisting CTL immunity to four recently described HER-2/neu–derived and HLA-A2–restricted "cytotoxic" peptides and to a novel one spanning amino acids 777–785 also with HLA-A2–binding motif. We utilized enzyme-linked immunosorbent spot (ELISpot) assay, which allows a quantitative and functional assessment of T cells directed against specific peptides after only brief in vitro incubation. CTL reactivity was determined with an interferon (IFN- ) ELISpot assay detecting T cells at the single cell level secreting IFN- . CTLp were defined as peptide-specific precursors per 106 peripheral blood mononuclear cells (PBMCs). Patients' PBMCs with increased CTLp were also tested against autologous tumor targets and peptide-pulsed dendritic cells (DCs) in cytotoxicity assays. We also studied patients with HER-2/neu-negative (-) tumors and healthy individuals. Of the HER-2/neu+ patients examined, 31% had increased CTLp to HER-2(9952), 19% to HER-2(9665), 16% to HER-2(9689), and 12.5% HER-2(9435), whereas only 2 of 32 patients (6%) responded to HER-2(9777). The CTLp recognizing HER-2(9952) were extremely high in two patients with breast cancer, one with lung cancer, and one with prostate cancer. None of the HER-2/neu- patients or healthy donors exhibited increased CTLp to any of these peptides. Besides IFN- production, preexisting CTL immunity to all five HER-2/neu peptides was also shown in cytotoxicity assays where patients' PBMCs with increased CTLp specifically lysed autologous tumor targets and autologous peptide-pulsed DCs. Our results demonstrate for the first time that (1) preexisting immunity to peptides HER-2(9435), HER-2(9952), HER-2(9689), HER-2(9665), and HER-2(9777) is present in patients with HER-2/neu+ tumors of distinct histology, (2) HER-2(9777) is a naturally processed peptide expressed on the surface of HER-2/neu+ tumors, as are the other four peptides, and (3) HER-2/neu+ prostate tumor cells can be recognized and lysed by autologous HER-2 peptide-specific CTL. Our findings broaden the potential application of HER-2/neu-based immunotherapy. |
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Keywords: | T-cell precursor HER-2/neu peptides Cancer patients Cytotoxicity IFN- /content/jjqwjjlkdj2aqpuh/xxlarge947.gif" alt=" gamma" align=" MIDDLE" BORDER=" 0" > production |
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