title: Natural T-cell response against MHC class I epitopes of epithelial cell adhesion molecule, her-2/neu, and carcinoembryonic antigen in patients with colorectal cancer.
abstract: The antigens epithelial cell adhesion molecule (Ep-CAM), her-2/neu, and carcinoembryonic antigen (CEA) are potential T-cell targets in antigen-specific vaccination-based cancer therapy. We performed this study to evaluate whether a natural specific T-cell response against these tumor-associated antigens (TAAs) already exists in patients with colorectal carcinoma (CRC). We used the IFN-gamma ELISPOT assay to detect circulating TAA-reactive T cells directly ex vivo in unstimulated peripheral blood mononuclear cells. We analyzed the T-cell response in peripheral blood mononuclear cells of 22 HLA-A2-positive patients with CRC and 8 HLA-A2-positive healthy subjects against 3 HLA A2-restricted peptide epitopes of the TAAs Ep-CAM (GLKAGVIAV), her-2/neu (IISAVVGIL), and CEA (YLSGANLNL). Seven of 22 patients but none of the 8 healthy subjects had T cells specifically secreting IFN-gamma in response to one to three of these antigens (n = 4, Ep-CAM; n = 5, her-2/neu; n = 6, CEA). In three of the seven responding patients, TAA-reactive T cells were further characterized by flow cytometry. In all three patients, the majority of these T cells have a CD3+CD8+IFN-gamma+CD69+CD45RA+ phenotype, resembling activated effector-type T cells. T-cell responses occurred only in patients with metastatic disease (Dukes' stages C and D). The results of this study indicate that natural T-cell responses against TAAs occur in approximately one-half of CRC patients with involvement of lymph nodes or distant metastases, but not in CRC patients with disease confined to the intestinum.
authors.affiliation: Medizinische Klinik III, Hematology, Oncology and Transfusion Medicine, University Hospital Benjamin Franklin, Free University Berlin, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Nagorsen
authors.forename: U
authors.initials: U
authors.lastname: Keilholz
authors.forename: L
authors.initials: L
authors.lastname: Rivoltini
authors.forename: A
authors.initials: A
authors.lastname: Schmittel
authors.forename: A
authors.initials: A
authors.lastname: Letsch
authors.forename: A M
authors.initials: AM
authors.lastname: Asemissen
authors.forename: G
authors.initials: G
authors.lastname: Berger
authors.forename: H J
authors.initials: HJ
authors.lastname: Buhr
authors.forename: E
authors.initials: E
authors.lastname: Thiel
authors.forename: C
authors.initials: C
authors.lastname: Scheibenbogen
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D000951:Antigens, Neoplasm / Q000276:immunology*; D002272:Carcinoembryonic Antigen / Q000276:immunology; D015815:Cell Adhesion Molecules / Q000276:immunology; D015179:Colorectal Neoplasms / Q000097:blood / Q000276:immunology* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D000071858:Epithelial Cell Adhesion Molecule; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation / Q000276:immunology*; D008297:Male; D009367:Neoplasm Staging; D010446:Peptide Fragments / Q000276:immunology / Q000494:pharmacology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D002272:Carcinoembryonic Antigen; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D010446:Peptide Fragments; D018719:Erb-b2 Receptor Tyrosine Kinases; C050928:carcinoma-associated antigen 17-1A