Enhanced DNA Vaccine Delivery to Protect Against Biothreat Agents

The objective of this proposal is to demonstrate the effectiveness of bacterial ghosts (BG) with internally immobilized DNA minicircles as an enhanced non-viral DNA vaccine and delivery system. Current methodologies for delivering DNA vaccines are either inefficient, do not target the appropriate cell types, contain unnecessary genetic elements or fail to elicit a protective immune response in the absence of a protein antigen boost. BG are non-living bacterial envelopes that deliver DNA constructs and/or protein antigens to a wide variety of cell types, including dendritic cells and macrophages and do not require the addition of adjuvant to induce an immune response. DNA minicircles contain only the necessary promoter and gene elements for a vaccine candidate protein and can be attached to the interior of BG. Both BG and DNA minicircles can be easily modified to include a mixture of different ORFs for use as a multi-agent or multi-life stage vaccine. In this proposal, BG containing immobilized DNA minicircles with gene sequences for Bacillus anthracis and Yersinia pestis antigens will be used to vaccinate small animals. Animals will undergo a scheduled vaccination scheme, the immune response will be assessed and the animals will be challenged to determine the efficacy of the vaccine.