Erschienen in:
01.09.2006
Depletion of CD4+CD25+ Regulatory T Cells Promotes a Tumor-Specific Immune Response in Pancreas Cancer–Bearing Mice
verfasst von:
Carsten T. Viehl, MD, Todd T. Moore, BS, Udaya K. Liyanage, MD, Daniel M. Frey, MD, Jesmin P. Ehlers, BS, Timothy J. Eberlein, MD, Peter S. Goedegebuure, PhD, David C. Linehan, MD
Erschienen in:
Annals of Surgical Oncology
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Ausgabe 9/2006
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Abstract
Background
Pancreas cancer–bearing mice have an increased prevalence of immunosuppressive CD4+CD25+ regulatory T cells (Treg). Depletion of Treg results in smaller tumors and prolonged host survival. The objective of this study was to evaluate the tumor-specific immune response after depletion of Treg alone or in combination with a cancer vaccine.
Methods
Four groups of C57BL/6 mice were challenged with pancreas adenocarcinoma cells (Pan02). The mice received four combinations of antibody-mediated Treg depletion and whole tumor cell vaccination: (1) no treatment, (2) Treg depletion only, (3) vaccination only, or (4) Treg depletion and vaccination. Splenocytes and lymphocytes from tumor-draining lymph nodes were analyzed for tumor-specific release of interferon γ by enzyme-linked immunosorbent spot assay.
Results
In Treg-depleted and vaccinated mice, a strong statistical trend toward smaller tumors (P = .05) and longer survival (P = .054) was found compared with untreated mice. Treg-depleted mice showed significantly more tumor-specific cells than undepleted mice (P = .02). The number of tumor-specific cells was significantly higher in tumor-draining lymph nodes than in the spleen (P = .002). Similarly, significantly more tumor-specific cells were found in spleens of Treg-depleted and vaccinated mice than in vaccinated-only mice (P = .009).
Conclusions
Depletion of Treg alone or in combination with a whole tumor cell vaccine promotes a tumor-specific immune response. Thus, strategies incorporating Treg depletion might improve the efficacy of cancer vaccines.