Hepatitis B DNA vaccine induces protective antibody responses in human non-responders to conventional vaccination.

A novel DNA vaccine against hepatitis B virus was administered intraepidermally by particle-mediated epidermal delivery (PMED) to 16 human subjects who demonstrated absent or non-sustainable responses to conventional hepatitis B vaccination. Eleven subjects received three doses of vaccine at 56-day intervals, and five subjects received only a single vaccination. Each dose of vaccine contained 4 microg of plasmid DNA encoding the hepatitis B surface antigen (HBsAg). The vaccine was safe and well tolerated. Remarkably, the DNA vaccine elicited antibody responses in 12 of the 16 subjects after a licensed subunit vaccine failed to induce a lasting response after >/=3 vaccinations. This study provides evidence in humans for protective immunogenicity of a particle-mediated DNA vaccine in subjects who have responded suboptimally to conventional vaccination.