Needle-free jet injection of DNA and protein vaccine of the far-eastern subtype of tick-borne encephalitis virus induces protective immunity in mice.

Tick-borne encephalitis virus (TBEV) causes severe encephalitis in humans. It is endemic in one area of Japan; however no commercial vaccine is available in that country. In this Japan-based study, the efficacy of subviral particles (SPs) of TBEV administered by needle-free injector was evaluated as a vaccine candidate. Inoculation with SP-encoding DNA by needle-free injector induced neutralizing antibodies more efficiently than when administered by needle and syringe, and mice vaccinated with one dose by needle-free injector survived challenge with a lethal dose of TBEV. These results suggest that SP vaccines delivered by needle-free injector can protect against TBEV infection.