Cross-priming by temozolomide enhances antitumor immunity of dendritic cell vaccination in murine brain tumor model.

Although chemotherapy remains among the best treatment options for most cancers, adjuvant therapies such as dendritic cell (DC)-based immunotherapy have been added to treatment protocols to destroy residual tumor cells. IFN-gamma secreting T cells specific for survivin was found after temozolomide (TMZ) treatment in C57BL/6 mice intracranial (i.c.) inoculated with GL26 cells. Furthermore, combination treatment with low-dose TMZ (2.5mg/kg/day, i.p.) chemotherapy followed by vaccination with survivin RNA-transfected DCs (1 x 10(6)cells/mouse, s.c.) enhanced T cells responses specific for survivin and improved survival rate compared with DC vaccination alone or TMZ treatment alone in tumor inoculated mice. However, these enhancements of T cells responses by TMZ treatment were not observed in mice without tumor inoculation. These results suggested that cross-priming by TMZ may enhance antitumor immunity of DC vaccination in murine brain tumor model.