Generation of potent and specific cellular immune responses via in vivo stimulation of dendritic cells by pNGVL3-hFLex plasmid DNA and immunogenic peptides.

Dendritic cells (DC) are the most potent professional antigen-presenting cells with exquisite capacity to interact with T cells to initiate strong primary cellular immune responses. The antigen-presenting capability of DC makes them attractive vehicles for the delivery of therapeutic cancer vaccines. Recently, we have demonstrated that the introduction of a recombinant gene encoding the human Flt3L gene into mice could result in the expansion of the DC population in vivo. In this report, we have introduced the human Flt-3L gene via naked DNA-based immunization in combination with the muc-1 tumor peptide to immunize mice. We demonstrated that the population of DC expanded following stimulation with the human Flt-3L gene in vivo is functional and they are able to elicit potent muc-1 peptide-specific cellular responses. The strategy described here allows the efficient generation of antigen-specific CTL immunity in vivo and has the potential to be applied in developing efficient protocols for antigen-specific immunotherapy of human malignancies.