Antigens encoded by DNA vaccines can induce all arms of the adaptive immune response, but to date they have proven most effective at inducing antigen-specific CD8+ T cells. The great majority of experiments have been carried out in small animal models, where these vac- cines work quite well; in a limited number of studies in primates (including humans), their effectiveness, although demonstrable, is somewhat diminished. Therefore, to accelerate the introduction of DNA vaccines into clinical and veterinary practice, it is important that their immunogenicity be enhanced. The rational...