title: NY-ESO-1 DNA vaccine induces T-cell responses that are suppressed by regulatory T cells.
abstract: OBJECTIVE
  Different vaccination strategies against the NY-ESO-1 antigen have been employed in an attempt to induce antitumor immune responses. Antigen-specific effector T-cell responses have been reported in a subset of vaccinated patients; however, these responses have not consistently correlated with disease regression. Here, we report for the first time clinical and immune responses generated by the NY-ESO-1 DNA vaccine administered by particle-mediated epidermal delivery to cancer patients.
  
  
  METHODS
  Eligible patients received treatment with the NY-ESO-1 DNA vaccine. Clinical outcomes and immune responses were assessed.
  
  
  RESULTS
  The NY-ESO-1 DNA vaccine was safely administered and induced both antigen-specific effector CD4 and/or CD8 T-cell responses in 93% (14 of 15) of patients who did not have detectable pre-vaccine immune responses. Despite the induction of antigen-specific T-cell responses, clinical outcomes consisted predominantly of progressive disease. Detectable effector T-cell responses were inconsistent and did not persist in all patients after completion of the scheduled vaccinations. However, high-avidity CD4 T-cell responses that were either undetectable pre-vaccine or found to be diminished at a later time during the clinical trial were detected in certain patients' samples after in vitro depletion of regulatory T cells.
  
  
  CONCLUSIONS
  Regulatory T cells play a role in diminishing vaccine-induced antigen-specific effector T-cell responses in cancer patients. The NY-ESO-1 DNA vaccine represents a feasible immunotherapeutic strategy to induce antigen-specific T-cell responses. Counteracting regulatory T-cell activity before vaccination may lead to prolonged effector T-cell responses and possibly antitumor responses in cancer patients.
authors.affiliation: Ludwig Institute for Cancer Research, New York Branch, Memorial Sloan-Kettering Cancer Center, New York, USA.
authors.forename: Sacha
authors.initials: S
authors.lastname: Gnjatic
authors.forename: Nasser K
authors.initials: NK
authors.lastname: Altorki
authors.forename: Derek Ng
authors.initials: DN
authors.lastname: Tang
authors.forename: Shi-Ming
authors.initials: SM
authors.lastname: Tu
authors.forename: Vikas
authors.initials: V
authors.lastname: Kundra
authors.forename: Gerd
authors.initials: G
authors.lastname: Ritter
authors.forename: Lloyd J
authors.initials: LJ
authors.lastname: Old
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Logothetis
authors.forename: Padmanee
authors.initials: P
authors.lastname: Sharma
mesh_terms: D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D019496:Cancer Vaccines / Q000009:adverse effects / Q000276:immunology*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000276:immunology / Q000628:therapy*; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*; D014611:Vaccination; D019444:Vaccines, DNA / Q000009:adverse effects / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; C104948:CTAG1B protein, human; D019496:Cancer Vaccines; D008565:Membrane Proteins; D019444:Vaccines, DNA