Improving DNA vaccines targeting viral infection

DNA vaccination techniques have been recently under intensive investigation both preclinically and in human studies aimed at impacting viral infection. Collectively, DNA vaccines expressing viral antigens induce both antigen-specific humoral and cellular immune responses which in model systems are capable of impacting viral infection. However, in clinical settings the potency of this approach is still under investigation. Efficacy is improved in specific circumstances through the addition of immunomodulatory molecules including cytokines as plasmid cassettes or through modification of the numbers of specific CpG sequences present in the backbone. Furthermore, combined vaccination schemes have been an important research focus for generating enhanced immunogenicity against viral infections. The ultimate utility of these approaches to prevent viral infection will require more work. However, improvements in the potency and focus of DNA vaccines present us with new opportunities for both basic research into protective immunity as well as novel strategies for immune therapy and prophylaxis.