Intradermal DNA vaccine delivery using vacuum-controlled, needle-free electroporation.

Intradermal delivery of DNA vaccines via electroporation (ID-EP) has shown clinical promise, but the use of needle electrodes is typically required to achieve consistent results. Here, delivery of a DNA vaccine targeting the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is achieved using noninvasive intradermal vacuum-EP (ID-VEP), which functions by pulling a small volume of skin tissue into a vacuum chamber containing noninvasive electrodes to perform EP at the injection site. Gene expression and immunogenicity correlated with EP parameters and vacuum chamber geometry in guinea pigs. ID-VEP generated potent humoral and cellular immune responses across multiple studies, while vacuum (without EP) greatly enhanced localized transfection but did not improve immunogenicity. Because EP was performed noninvasively, the only treatment site reaction observed was transient redness, and ID-VEP immune responses were comparable to a clinical needle-based ID-EP device. The ID-VEP delivery procedure is straightforward and highly repeatable, without any dependence on operator technique. This work demonstrates a novel, reliable, and needle-free delivery method for DNA vaccines.

In Vivo Assembly of Nanoparticles Achieved through Synergy of Structure-Based Protein Engineering and Synthetic DNA Generates Enhanced Adaptive Immunity.

Nanotechnologies are considered to be of growing importance to the vaccine field. Through decoration of immunogens on multivalent nanoparticles, designed nanovaccines can elicit improved humoral immunity. However, significant practical and monetary challenges in large-scale production of nanovaccines have impeded their widespread clinical translation. Here, an alternative approach is illustrated integrating computational protein modeling and adaptive electroporation-mediated synthetic DNA delivery, thus enabling direct in vivo production of nanovaccines. DNA-launched nanoparticles are demonstrated displaying an HIV immunogen spontaneously self-assembled in vivo. DNA-launched nanovaccines induce stronger humoral responses than their monomeric counterparts in both mice and guinea pigs, and uniquely elicit CD8+ effector T-cell immunity as compared to recombinant protein nanovaccines. Improvements in vaccine responses recapitulate when DNA-launched nanovaccines with alternative scaffolds and decorated antigen are designed and evaluated. Finally, evaluation of functional immune responses induced by DLnanovaccines demonstrates that, in comparison to control mice or mice immunized with DNA-encoded hemagglutinin monomer, mice immunized with a DNA-launched hemagglutinin nanoparticle vaccine fully survive a lethal influenza challenge, and have substantially lower viral load, weight loss, and influenza-induced lung pathology. Additional study of these next-generation in vivo-produced nanovaccines may offer advantages for immunization against multiple disease targets.

Integration of needle-free jet injection with advanced electroporation delivery enhances the magnitude, kinetics, and persistence of engineered DNA vaccine induced immune responses.

The combination of optimized DNA constructs, improved formulations and advanced in vivo electroporation (EP) has been shown to generate potent and efficacious immune responses in the clinic. Needle-free jet injection has also been reported to improve DNA vaccine delivery over standard needle and syringe in clinical trials. Here we investigated the impact of combined jet injection and EP (Jet-EP) delivery on muscle transfection efficiency and DNA vaccine immunogenicity in rabbits and nonhuman primates (NHPs) compared to jet injection alone. Our results show that the addition of EP significantly enhanced in vivo DNA transfection efficiency of rabbit muscle over jet injection alone. Jet-EP delivery augmented the rate and magnitude of DNA vaccine induced humoral and cellular responses over jet injection alone in both rabbits and NHPs. Jet-EP delivery also resulted in higher proportions of polyfunctional antigen specific T cells producing IFNγ, IL-2, and/or TNFα. Elevated antibody levels were sustained nine months post immunization in NHPs immunized with a DNA vaccine using Jet-EP delivery, far outperforming jet delivery alone. Our results provide proof-of-concept that addition of advanced EP to needle-free jet injection delivery improves in vivo DNA transfection efficiency, increasing the magnitude, rate and duration of cellular and humoral immune responses to DNA vaccines. This combination likely has significant advantages in important vaccine and immunotherapy settings.