Cyclophosphamide Potentiates the Antitumor Effect of Immunization with Injection of Immature Dendritic Cells into Irradiated Tumor

Abstract

Growth of a tumor on the left flank was suppressed by direct injection of immature DCs (iDCs) into the irradiated tumor on the right thigh (IR/DC). This antitumor immune effect of IR/DC was enhanced by pretreatment with CTX (CTX+IR/DC) and this effect was related with increased number of tumor-specific IFN-γ secreting T cells and decreased ratio of CD4⁺CD25⁺/CD4⁺ T cells. The treatment with CTX+IR/DC increased or decreased the levels of IL-2 or IL-10, respectively. These results demonstrated that antitumor effect of IR/DC could be augmented by pretreatment with low-dose CTX, suggesting a new antitumor therapeutic modality of chemoradioimmunotherapy.

Keywords:

• Dendritic cells
• Cancer immunotherapy
• Cyclophosphamide
• Radiotherapy

ACKNOWLEDGMENTS

This work was supported by Nuclear Medical Sciences R&D program (to C.-D. K. and Y.-S. P) through the Dongnam Institute of Radiological & Medical Sciences (Code: 50591-2010) and Federation of Busan Science and Technology funded by Busan Metropolitan City and Gijang County, and MRC Program through NRF grant [R13-2005-009 (to S.-H. K.)] funded by the Ministry of Education, Science and Technology.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.