Progress Towards a Therapeutic HIV DNA Vaccine

Antiretroviral therapy (ART) reduces HIV replication to undetectable levels and prevents AIDS but cannot cure the infection and discontinuing ART results in viral rebound. Therefore, a primary goal of HIV therapeutic vaccine research is to induce potent HIV-specific immunity that could control viremia without ART, a so-called "functional cure" that eliminates the need for lifelong ART. DNA vaccines have several features that make them an attractive modality for an HIV therapeutic vaccine: they are easy to manufacture, induce T-cell and antibody responses without anti-vector immunity, and do not involve ex vivo manipulations of patient cells.

This review covers the progress in developing therapeutic HIV DNA vaccines, emphasizing delivery innovations to enhance vaccine immunogenicity. A central theme is a transition from needle injection delivery to the muscle toward using more sophisticated devices to target the skin and/or increasing transfection efficiency.

There are multiple barriers to an effective therapeutic HIV DNA vaccine. While variables such as delivery, adjuvants, and immunogen design have been extensively explored, combining DNA vaccines with complementary approaches is underdeveloped. Complementary approaches include co-administration with latency reversal agents, immune checkpoint blockade, and targeting conserved fitness-constrained portions of the virus.