[Present status of basic studies and development of DNA vaccines]

Inoculation with plasmid DNA encoding immunogenic proteins of microorganisms induces specific antibodies and cytotoxic T lymphocytes. This method, termed DNA immunization, can provides protective immunity against viruses, bacteria and parasites in animal models. However, the mechanisms by which DNA vaccines induce immunity are not completely understood. Phase 1 studies of DNA vaccines in humans seem to have promising results, although the question about safety of DNA vaccine has not been confirmed yet. DNA vaccines have some advantages over currently used vaccines: inactivated and live attenuated vaccines. New knowledge is accumulating day by day. This approach may provide a new type of vaccines against various microorganisms in the near future.