Intradermal DNA immunization of mice against influenza A virus using the novel PowderJect system.

The PowderJect system, a device that uses compressed helium gas to accelerate microscopic particles into the skin, was used as a delivery system for DNA vaccines to elicit a virus-specific cytotoxic T cell response (CTL) in mice. Transient expression of beta-galactosidase (beta-Gal) was observed in the epidermis when gold particles coated with beta-Gal expression plasmid were delivered to mouse skin with the device. When DNA encoding the nucleoprotein gene (NP) of influenza A virus was used to coat gold particles, a strong and specific anti-NP CTL response was elicited by immunizations with nanogram amounts of the NP DNA vector. This study shows the potential for application of the PowderJect system to intradermal delivery of DNA in order to elicit an immune response.