Comparative performance of a licensed anthrax vaccine versus electroporation based delivery of a PA encoding DNA vaccine in rhesus macaques.

DNA vaccination is a promising immunization strategy that could be applied in the development of vaccines for a variety of prophylactic and therapeutic indications. Utilizing anthrax protective antigen as a model antigen, we demonstrate that electroporation mediated delivery enhanced the immunogenicity of DNA vaccines in nonhuman primates over 100-fold as compared to conventional intramuscular injection. Two administrations of a DNA vaccine with electroporation elicited anthrax toxin neutralizing antibody responses in 100% of rhesus macaques. Toxin neutralizing antibodies were sustained for the nearly 1-year study duration and were correlated with protection against subsequent lethal Bacillus anthracis spore challenge. Collectively, electroporation mediated DNA vaccination conferred protection comparable to that observed following vaccination with an FDA approved anthrax vaccine.