Document Type : Original Article(s)
Authors
- Koki Matsuyama 1
- Takeshi Ota 1
- Junko Baba 1
- Takao Miyabayashi 1
- Satoshi Watanabe 1
- Hiroshi Kagamu 1
- Ichiei Narita 1
- Koh Nakata 2
- Hirohisa Yoshizawa 2
1 Division of Respiratory Medicine, Department of Homeostatic Regulation and Development, Niigata University, Niigata, Japan
2 Bioscience Medical Research Center, Niigata University Medical and Dental Hospital, Niigata, Japan
Abstract
Background: Nonmyeloablative chemotherapy followed by adoptive immunotherapy is an attractive strategy for depleting regulatory T cells in the host. However, its efficacy is transient. Here, we aim to investigate whether cyclic chemoim- munotherapy has therapeutic efficacy against cancer.Methods:We examined the efficacy of cyclic chemoimmunotherapy with cyclophos- phamide and adoptively transferred effector T cells against 5-day, established MCA205 murine skin sarcomas.Results: Cyclophosphamide administration followed by adoptive immunotherapy augmented the trafficking of effector T cells into established tumors. Further, multiple cyclophosphamide administrations helped effector T cells to persist at the sites. Chemoimmunotherapy achieved complete tumor regression even with the transfer of a limited number of effector T cells (5×106).Conclusion: Cyclic chemoimmunotherapy, which maintains adoptively transferred T cells by impairing regulatory T cells, is a potentially suitable treatment for established tumors.
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