Vaccinations with dendritic cells primed with apoptotic tumor cells can elicit preventive antitumor immunity in a poorly immunogenic animal model of squamous cell carcinoma

BACKGROUND: Dendritic cells (DCs) can effectively mediate the prevention and regression of a variety of solid tumors. However, not much has been determined about their efficacy for the prevention of squamous cell carcinoma (SCC), partly because there are no known tumor-specific antigens or low immunogenicity for this tumor. The authors aimed to determine the preventive effect of DC-based immunotherapy in a SCC animal model. METHODS: Bone marrow derived DCs of C3H/He mice were pulsed with ultraviolet-B-irradiated apoptotic SCCVII cells, which are known as a poorly immunogenic SCC cell line. After the animals were vaccinated with these DCs, a tumorigenic dosage of SCCVII cells was subcutaneously injected and the tumor growth assessed. RESULTS: Animals pretreated with apoptotic SCCVII cell-pulsed DCs showed tumor extinction within 2 weeks after forming a small tumor, or there was no tumor formation at all, as seen in 81% of the mice; in the remaining 19% of the mice, tumor growth was significantly retarded compared with the control groups (P = .0029). The SCCVII cell-specific T-cell response was observed in the immunized mice. CONCLUSION: The adoptive transfer of DCs primed with apoptotic tumor cells can hopefully serve as an effective preventive vaccine, even in poorly immunogenic SCC.