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

Abstract

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. 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. 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. The adoptive transfer of DCs primed with apoptotic tumor cells can hopefully serve as an effective preventive vaccine, even in poorly immunogenic SCC.