title: Recognition of prostate and breast tumor cells by helper T lymphocytes specific for a prostate and breast tumor-associated antigen, TARP.
abstract: OBJECTIVE
  T cell-based immunotherapy via the in vitro or in vivo expansion of prostate tumor-associated antigen (TAA)-specific T lymphocytes is one of the most promising therapeutic approaches to treat prostate cancer. T-cell alternate reading frame protein (TARP) is a mitochondrial protein that is specifically expressed in prostate epithelial cells. We have done experiments aimed at identifying helper T lymphocyte (HTL) epitopes for TARP for the design of T cell-based immunotherapy for prostate cancer.
  
  
  METHODS
  Dendritic cells from normal donors were pulsed with synthetic peptides derived from TARP, which were predicted to serve as HTL epitopes. These dendritic cells were used to stimulate CD4(+) T cells in vitro to trigger HTL responses against TARP. T-cell responses to these peptides were also studied with lymphocytes from prostate cancer patients.
  
  
  RESULTS
  The two peptides, TARP(1-14) and TARP(14-27), were shown to elicit effective in vitro HTL responses using lymphocytes from both normal volunteers and prostate cancer patients. Peptide TARP(1-14)-reactive HTLs were found restricted by HLA-DR53 and could recognize naturally processed protein antigen derived from tumor cells, which was presented by autologous dendritic cells. Most significantly, stimulation with peptide TARP(14-27) generated four HTL lines restricted by HLA-DR1, HLA-DR9, HLA-DR13, and HLA-DR15, some of which capable of recognizing naturally processed antigens presented by dendritic cell or directly by TARP-positive tumor cells.
  
  
  CONCLUSIONS
  Our results show that TARP constitutes a TAA that can be recognized by tumor-reactive HTL. The newly described TARP epitopes could be used to optimize and improve T-cell epitope-based immunotherapy against prostate and other tumors expressing TARP.
authors.affiliation: Department of Pathology, Asahikawa Medical College, Asahikawa, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nagato
authors.forename: Kensuke
authors.initials: K
authors.lastname: Oikawa
authors.forename: Keisuke
authors.initials: K
authors.lastname: Sato
authors.forename: Shoji
authors.initials: S
authors.lastname: Kimura
authors.forename: Naoko
authors.initials: N
authors.lastname: Aoki
authors.forename: Ryusuke
authors.initials: R
authors.lastname: Omiya
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Tateno
authors.forename: Esteban
authors.initials: E
authors.lastname: Celis
mesh_terms: D017951:Antigen Presentation; D000951:Antigens, Neoplasm; D001943:Breast Neoplasms / Q000276:immunology / Q000473:pathology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology*; D003713:Dendritic Cells; D000939:Epitopes; D005260:Female; D006801:Humans; D007167:Immunotherapy; D008297:Male; D009687:Nuclear Proteins / Q000276:immunology*; D011471:Prostatic Neoplasms / Q000276:immunology / Q000473:pathology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D000939:Epitopes; D009687:Nuclear Proteins; C413185:TARP