Induction of Th1-type immunity and tumor protection with a prostate-specific antigen DNA vaccine

Cancer Immunol Immunother. 2005 Nov;54(11):1082-94. doi: 10.1007/s00262-005-0687-0. Epub 2005 Jul 27.


Prostate specific antigen (PSA) is a serum marker that is widely used in the detection and monitoring of prostate cancer. Though PSA is a self-antigen, T cell responses to PSA epitopes have been detected in healthy men and prostate cancer patients, suggesting it may be used as a target for active immunotherapy of prostate cancer. A PSA DNA vaccine (pPSA) was evaluated in mice and monkeys for its ability to induce antigen-specific immune responses. Mice immunized intradermally with pPSA demonstrated strong PSA-specific humoral and cellular immunity. The anti-PSA immune responses were skewed toward Th1, as shown by high IFNgamma and IL-2 production. The immune response was sufficient to protect mice from challenge with PSA-expressing tumor cells. Tumor protection was durable in the absence of additional vaccination, as demonstrated by protection of vaccinated mice from tumor rechallenge. Furthermore, pPSA vaccination induced PSA-specific antibody titers in male cynomolgus monkeys, which express a closely related PSA gene. These results demonstrate that vaccination with pPSA may be able to break tolerance and can induce an immune response that mediates tumor protection.

MeSH terms

  • Animals
  • Antibodies / blood
  • Female
  • Humans
  • Immunization
  • Interferon-gamma / biosynthesis
  • Macaca fascicularis
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Prostate-Specific Antigen / immunology*
  • Prostatic Neoplasms / prevention & control*
  • T-Lymphocytes, Cytotoxic / immunology
  • Th1 Cells / immunology*
  • Vaccines, DNA / immunology*


  • Antibodies
  • Vaccines, DNA
  • Interferon-gamma
  • Prostate-Specific Antigen