NSU-MD Faculty Articles

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

Publication Title

The Journal of clinical investigation

Publisher

American Society for Clinical Investigation

ISSN

0021-9738

Publication Date

12-1-2005

Keywords

Aged, Antigens, Neoplasm, CD28 Antigens, CD3 Complex, CD4-Positive T-Lymphocytes, Cancer Vaccines, Carcinoma, Renal Cell, Cell Separation, Dendritic Cells, Diphtheria Toxin, Enzyme-Linked Immunosorbent Assay, Female, Flow Cytometry, Humans, Immunosuppressive Agents, Interferon-gamma, Interleukin-2, Interleukin-4, Kidney Neoplasms, Leukocytes, Mononuclear, Male, Middle Aged, Neoplasm Metastasis, Neoplasms, RNA, RNA, Neoplasm, Receptors, Interleukin-2, Reverse Transcriptase Polymerase Chain Reaction, T-Lymphocytes, T-Lymphocytes, Regulatory, Time Factors, Transfection

Abstract

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.

DOI

10.1172/JCI25947

Volume

115

Issue

12

First Page

3623

Last Page

3633

Disciplines

Medicine and Health Sciences

Peer Reviewed

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