Purpose: Anthrax is a lethal bacterial disease caused by gram-positive bacterium Bacillus
anthracis and vaccination is a desirable method to prevent anthrax infections. In the present study, DNA
vaccine encoding a protective antigen of Bacillus anthracis was prepared and we investigated the influence
of DNA electrotransfer in the skin on the induced immune response and biodistribution.
Methods and Results: The tdTomato reporter gene for the whole animal in vivo imaging was used to
assess gene transfer efficiency into the skin as a function of electrical parameters. Compared to that with
25 V, the transgene expression of red fluorescent protein increased significantly when a voltage of 90 V
was used. Delivery of DNA vaccines expressing Bacillus anthracis protective antigen domain 4 (PAD4)
with an applied voltage of 90 V induced robust PA-D4-specific antibody responses. In addition, the
in vivo fate of anthrax DNA vaccine was studied after intradermal administration into the mouse. DNA
plasmids remained at the skin injection site for an appropriate period of time after immunization. Intradermal
administration of DNA vaccine resulted in detection in various organs (viz., lung, heart, kidney,
spleen, brain, and liver), although the levels were significantly reduced.
Conclusion: Our results offer important insights into how anthrax DNA vaccine delivery by intradermal
electroporation affects the immune response and biodistribution of DNA vaccine. Therefore, it may
provide valuable information for the development of effective DNA vaccines against anthrax infection.