Abstract

Abstract Nucleic acid vaccines play important roles in the prevention and treatment of diseases. However, limited immunogenicity remains a major obstacle for DNA vaccine applications in the clinic. To address the issue, the present study investigates a cocktail approach to DNA vaccination. In this proof‐of‐the‐concept study, the cocktail consists of two DNAs encoding viral hemagglutinin (HA) and granulocyte‐macrophage colony stimulatory factor (GM‐CSF), respectively. Data from the study demonstrate that recruitment and activation of antigen‐presenting cells (APCs) can be substantially improved by spatiotemporal regulation of GM‐CSF and HA expressions at the site of vaccination. The types of recruited APCs and their phenotypes are also controllable by adjusting the cocktail compositions. Compared to the mono‐ingredient vaccine, the optimized cocktail vaccine is able to enhance the anti‐viral humoral and T cell immune responses. No significant systemic inflammation is detected after either prime or boost immunization using the cocktail vaccine. Data in the study suggest that the DNA cocktail is a safe, effective, and controllable platform for improving vaccine efficacy.