A major advantage of DNA vaccination is the ability to induce both humoral and cellular immune responses. DNA vaccines are currently used in veterinary medicine, but have not achieved widespread acceptance for use in humans due to their low immunogenicity in early clinical studies. However, recent clinical data have re-established the value of DNA vaccines, particularly in priming high-level antigen-specific antibody responses. Several approaches have been investigated for improving DNA vaccine efficacy, including advancements in DNA vaccine vector design, the inclusion of genetically engineered cytokine adjuvants, and novel non-mechanical delivery methods.

Modern DNA vaccine design generally relies on synthesis of the nucleic acid and possibly one-step cloning into the plasmid vector, reducing both the cost and the time to manufacture. Plasmid DNA is also extremely stable at room temperature, reducing the need for a cold chain during transportation. Furthermore, DNA vaccination has an excellent safety profile in the clinic, with the most common side effect being mild inflammation at the injection site. Importantly, DNA vaccines provide a safe, non-live vaccine approach to inducing balanced immune responses, as the in vivo production of antigen allows for presentation on both class I and class II major histocompatibility complex (MHC) molecules. This elicits antigen specific antibodies, as well as cytotoxic T lymphocyte responses (CTL), something that remains elusive in most non-live vaccines. DNA vaccines have also demonstrated the ability to generate follicular T helper populations which are critical for the induction of high quality antigen-specific B cell responses.

Regards

John
Editorial Assistant
Immunogenetics Open Access