Combination of CTL-associated antigen-4 blockade and depletion of CD25 regulatory T cells enhance tumour immunity of dendritic cell-based vaccine in a mouse model of colon cancer

Scand J Immunol. 2010 Feb;71(2):70-82. doi: 10.1111/j.1365-3083.2009.02355.x.


Immune regulation has been shown to be involved in the progressive growth of some murine tumours. Interruption of immune regulatory pathways via CTL-associated antigen-4 (CTLA-4) blockade or removal of CD4(+) CD25(+) regulatory T (Treg) cells appears to be a promising strategy for cancer immunotherapy. In this study, we tested the hypothesis that the combination of CTLA-4 blockade and depletion of Treg cells would improve the potency of dendritic cell (DC)-based vaccine in a clinically relevant mouse model, which is transgenic for both carcinoembryonic antigen (CEA) and HLA-A2 for the treatment of colon carcinoma in a therapeutic setting. We found that administration of anti-CD25 antibody prior to vaccination or systemic administration of anti-CTLA-4 antibody with the vaccine improved tumour-free survival against CEA-expressing tumours compared with mice immunized with DC-based vaccine alone. However, the efficacy of the vaccine proved to be most effective when anti-CTLA-4 antibody was combined with Treg inhibition. This vaccination strategy dramatically improved the tumour-free survival and allowed the development of long-lasting immune responses. The combined vaccination strategy resulted in increased secretion of IFN-gamma and enhanced HLA-A2-restricted CEA-specific CTL responses. Furthermore, coadministration of anti-CD25 and anti-CTLA-4 antibodies along with the vaccine was effective against more advanced tumours. These results provide evidence that simultaneous blockade of T-cell regulatory pathways is a promising approach for the induction of therapeutic antitumour immunity against CEA(+) colon carcinoma.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antibodies, Antinuclear / blood
  • Antibodies, Antinuclear / immunology
  • Antigens, CD / immunology
  • CTLA-4 Antigen
  • Cancer Vaccines / immunology*
  • Carcinoembryonic Antigen / immunology
  • Cell Separation
  • Colonic Neoplasms / immunology*
  • Colonic Neoplasms / therapy
  • Dendritic Cells / transplantation*
  • Enzyme-Linked Immunosorbent Assay
  • Flow Cytometry
  • HLA-A2 Antigen / immunology
  • Immunotherapy / methods*
  • Interleukin-2 Receptor alpha Subunit / antagonists & inhibitors
  • Interleukin-2 Receptor alpha Subunit / immunology
  • Lymphocyte Depletion
  • Mice
  • Mice, Transgenic
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocytes, Regulatory / immunology*


  • Antibodies, Antinuclear
  • Antigens, CD
  • CTLA-4 Antigen
  • Cancer Vaccines
  • Carcinoembryonic Antigen
  • Ctla4 protein, mouse
  • HLA-A2 Antigen
  • Interleukin-2 Receptor alpha Subunit