DNA vaccines: what can we expect?

Direct injection of plasmid DNA in vivo was recently shown to induce both prolonged expression of encoded proteins and strong specific immune responses with particular features. Induction of specific antibodies, of CD8+ T lymphocytes, and of CD4+ T lymphocytes differentiated toward the TH1-like phenotype have been achieved in animal models of diseases for which either no vaccines currently exist, or for which vaccine optimization is yet needed. These promising initial results, along with the specific biological characteristics of DNA vaccines that render them particularly interesting in terms of vaccine production, open new perspectives in terms of immunization at a global level. The potential capacities of DNA vaccines to meet the challenge of inducing protection against specific target diseases or for population target groups currently identified as health priorities are reviewed here together with their possible drawbacks.