Enhancement of vaccine-mediated antitumor immunity in cancer patients after depletion of regulatory T cells.

Journal Article (Clinical Trial;Journal Article)

In this study, we investigated whether elimination of CD4+/CD25+ Tregs using the recombinant IL-2 diphtheria toxin conjugate DAB(389)IL-2 (also known as denileukin diftitox and ONTAK) is capable of enhancing the immunostimulatory efficacy of tumor RNA-transfected DC vaccines. We show that DAB(389)IL-2 is capable of selectively eliminating CD25-expressing Tregs from the PBMCs of cancer patients without inducing toxicity on other cellular subsets with intermediate or low expression of CD25. DAB(389)IL-2-mediated Treg depletion resulted in enhanced stimulation of proliferative and cytotoxic T cell responses in vitro but only when DAB(389)IL-2 was omitted during T cell priming. DAB(389)IL-2 significantly reduced the number of Tregs present in the peripheral blood of metastatic renal cell carcinoma (RCC) patients and abrogated Treg-mediated immunosuppressive activity in vivo. Moreover, DAB(389)IL-2-mediated elimination of Tregs followed by vaccination with RNA-transfected DCs significantly improved the stimulation of tumor-specific T cell responses in RCC patients when compared with vaccination alone. Our findings may have implications in the design of immune-based strategies that may incorporate the Treg depletion strategy to achieve potent antitumor immunity with therapeutic impact.

Full Text

Duke Authors

Cited Authors

  • Dannull, J; Su, Z; Rizzieri, D; Yang, BK; Coleman, D; Yancey, D; Zhang, A; Dahm, P; Chao, N; Gilboa, E; Vieweg, J

Published Date

  • December 2005

Published In

Volume / Issue

  • 115 / 12

Start / End Page

  • 3623 - 3633

PubMed ID

  • 16308572

Pubmed Central ID

  • PMC1288834

International Standard Serial Number (ISSN)

  • 0021-9738

Digital Object Identifier (DOI)

  • 10.1172/JCI25947


  • eng

Conference Location

  • United States