Her-2/neu-derived peptides are tumor-associated antigens expressed by human renal cell and colon carcinoma lines and are recognized by in vitro induced specific cytotoxic T lymphocytes.
The Her-2/neu oncogene encodes a Mr 185,000 transmembrane protein with homology to the epidermal growth factor receptor. It is overexpressed in 30-40% of breast and ovarian cancers, and this overexpression was shown to correlate with aggressiveness of malignancy and poor prognosis. Using tumor-associated lymphocytes isolated from patients with ovarian or breast cancer, several HLA-A2-restricted, Her-2/neu-derived peptides were identified. Further studies revealed that these tumor-associated CTLs can also lyse other tumors, including non-small cell lung and pancreatic cancer cells, suggesting that Her-2/neu epitopes are shared between several distinct types of epithelial tumors. To analyze whether Her-2/neu epitopes are tumor-associated antigens for renal cell carcinoma (RCC) and colon carcinoma, we induced Her-2/neu peptide-specific CTL responses by primary in vitro immunization and used these CTLs to determine the presentation of Her-2/neu epitopes on human tumor lines. Autologous dendritic cells (DCs) generated from peripheral blood monocytes were pulsed with Her-2/neu-derived peptides E75 and GP2 and used as antigen-presenting cells for CTL priming. High CTL activity toward peptide-pulsed targets was obtained after two weekly restimulations. CTLs induced with DCs generated in the presence of TNF-alpha elicited a higher cytotoxic activity when they were stimulated with the cognate peptide than did CTLs induced with DCs grown in granulocyte macrophage colony-stimulating factor and interleukin 4 alone. The cytotoxicity of induced CTLs was antigen specific and HLA-A2 restricted. Furthermore, these CTLs lysed, in a MHC- and antigen-restricted fashion, not only breast cancer cells but also colon carcinoma and RCC cell lines expressing Her-2/neu. The cytotoxic activity against tumor cells was blocked by cold HLA-A2-positive targets pulsed with the cognate peptide in cold target inhibition assay and by anti-HLA-A2 monoclonal Ab. These results suggest that epitopes derived from Her-2/neu protein might be attractive candidates for broadly applicable vaccines and may prove useful for adoptive immunotherapies designed for colon carcinoma or RCC.
Brossart
P
P
Department of Hematology, Oncology and Immunology, University of Tübingen, Germany.
Stuhler
G
G
Flad
T
T
Stevanovic
S
S
Rammensee
H G
HG
Kanz
L
L
Brugger
W
W
D000951:Antigens, Neoplasm / Q000276:immunology*; D001943:Breast Neoplasms / Q000276:immunology; D002460:Cell Line; D003110:Colonic Neoplasms / Q000276:immunology*; D003713:Dendritic Cells; D015789:HLA-A2 Antigen / Q000276:immunology; D006801:Humans; D007680:Kidney Neoplasms / Q000276:immunology*; D010455:Peptides / Q000276:immunology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D015789:HLA-A2 Antigen; D010455:Peptides; D018719:Erb-b2 Receptor Tyrosine Kinases