Because of the lack of full characterization of
tumor associated
antigens for solid
tumors, whole
antigen use is a convenient approach to
tumor vaccination.
Tumor RNA and apoptotic
tumor cells have been used as a source of whole
tumor antigen to prepare dendritic cell (DC) based
tumor vaccines, but their efficacy has not been directly compared. Here we compare directly
RNA electroporation and pulsing of DCs with whole
tumor cells killed by ultraviolet (UV) B radiation using a convenient
tumor model expressing human papilloma virus (HPV) E6 and E7 oncogenes. Although both approaches led to DCs presenting
tumor antigen, electroporation with
tumor cell total
RNA induced a significantly higher frequency of
tumor-reactive IFN-gamma secreting T cells, and E7-specific CD8+ lymphocytes compared to pulsing with UV-irradiated
tumor cells. DCs electroporated with
tumor cell
RNA induced a larger
tumor infiltration by T cells and produced a significantly stronger delay in
tumor growth compared to DCs pulsed with UV-irradiated
tumor cells. We conclude that electroporation with whole
tumor cell
RNA and pulsing with UV-irradiated
tumor cells are both effective in eliciting antitumor immune response, but
RNA electroporation results in more potent
tumor vaccination under the examined experimental conditions.