Combination vaccine of dendritic cells (DCs) and T cells effectively suppressed preestablished malignant melanoma in mice.

The study aims at establishing a novel vaccine procedure, using bone marrow-derived DCs that have ingested apoptotic B16 melanoma (DCs(+)), alone or in combination with splenic T lymphocytes from a syngenic donor. Co-immunization with DCs(+) and T cells showed the highest antitumor potential against preestablished B16 tumor in mice, in which CTL and NK cytotoxicities were drastically elevated, while either DCs(+) alone, naive DCs (DCs(-)) alone, or a mixture of DCs(-) and T cells induced less significant therapeutic outcomes. Use of extracellular matrix proteins elevated antitumor activity of DC(-)/T cell vaccine. Compared with the CD8(+) cells, the CD4(+)T cells more remarkably improved the efficacy of DC-based immunotherapy. The present system may be a feasible therapeutic modality to eradicate malignancies including melanoma.