Superiority of needle-free transdermal plasmid delivery for the induction of antigen-specific IFNgamma T cell responses in the dog.

Although successful needle-free DNA vaccination has been described on several occasions, the true benefit of this delivery technology over needle-based injections for DNA vaccination of dogs has not yet been documented. We conducted a side-by-side comparison of needle-free transdermal plasmid delivery vs. intramuscular vs. intradermal needle-based delivery of the same plasmid in dogs. Our data confirmed the importance of the route of plasmid delivery and further established the unique potential of needle-free transdermal plasmid delivery to elicit strong antigen-specific, hTyr-specific IFNgamma T in the dog. Further, this study demonstrated that properly enabled DNA vaccination has the potential to trigger very significant cell-based immune responses in dogs, establishing needle-free transdermal plasmid delivery as a critical technology for successful immunotherapy of cancer and/or chronic infectious diseases in companion animal medicine.