DNA-Nanoparticles (DNA-NP) for Antigen Presentation and Vaccine Design for Aerosolized Pathogens

Venezuelan equine encephalitis virus (VEEV) is classified as a category B select agent pathogen by the Centers for Disease Control and Prevention as it has the potential to pose a severe threat to human health. VEEV is primarily a mosquito-transmitted virus that results in natural infections of human and animals in various regions of the world. These natural infections are usually self-limiting and cause a mild flu-like disease. In some cases, the infection can proceed to an encephalitic outcome. VEEV is a serious threat to the Warfighter because it is highly stable and infectious as an aerosol. Indeed, in the aerosolized form, VEEV gains direct access to the brain after bypassing the blood-brain barrier via infection of the olfactory neurons. This leads to short-term and long-term neurological consequences including encephalitis and serious complications such as seizure and paralysis. In its ability to cause rapid infection and disease, VEEV is a prototype for several other biological threats to the Warfighter that result in encephalitic outcomes (Rift Valley fever virus [RVFV] or Dengue virus) and hemorrhagic outcomes (RVFV, Ebola virus, Marburg virus). Given the extreme infectious potential of VEEV in aerosol form, the short time required for the virus to gain access to the brain, delayed appearance of symptoms, and the potential devastating neurological outcomes, the threat for Warfighters is extremely serious. The advantages of a swift, safe, and effective vaccination strategy will include pathogen control early post-exposure and limiting the risk of long-term effects in the infected person. A critical unmet need in countermeasure, specifically vaccine development for the above-mentioned high priority pathogens, is the lack of a versatile platform that can function as a tool to assess vaccine candidate developability while also maintaining immunogenic potential. Such a platform technology will be an invaluable tool to develop an array of vaccines for the above-mentioned pathogens in a high-throughput manner. This proposal addresses that unmet need and proposes a novel solution to develop a biocompatible DNA-nanoparticles (DNA-NPs)-based tool to display immunogenic antigens with controlled nanoscale organization and stoichiometry for in vitro screening based on antigen nanoscale presentation. The prioritized candidate will be subsequently validated using in vivo models. By using this strategy, we will be able to present multiple antigens and adjuvants on a single DNA-NPs maximizing the potential for promoting a long-term protection in a safe and controlled manner and assess the impact on immune responsiveness. This tool, while being evaluated using VEEV as a prototype aerosolized pathogen, has the potential to be broadly applicable to other pathogen threats that the Warfighter may be exposed to. This strategy operates under the hypothesis that controlling the specific 3D organization and stoichiometry of the surface antigens is a key factor to effectively induce a strong immune response against VEEV. By using biocompatible DNA-NPs to display several copies of E1 an E2, the risk of serious side effects caused by the attenuated candidate vaccine strategy will be controlled while maintaining immunogenic potential. We hypothesized that these unique DNA-NPs presenting antigens have the potential to promote strong humoral and cellular immune response by increasing lymphatic trafficking and uptake by APCs. The specific aims of this effort are: (1) to design and assemble DNA-NPs displaying VEEV envelope glycoprotein E1 and E2 that can efficiently target antigen presenting cells in vitro and (2) to demonstrate protection using this DNA-NPs-based antigen presenting platform in the context of an aerosol challenge with virulent virus. The anticipated immediate outcome of this study is a well-characterized versatile DNA-NP-based platform displaying multiple copies of E1 and E2 in prescribed organization that has demonstrated in vivo efficacy in a mouse model of VEEV aerosol exposure. Long-term continuation of the proposed efforts will include extending the studies to aerosol exposure models for VEEV in nonhuman primates. The broad implications of this study include the application of this versatile DNA-NP-based tool to multiple aerosolized pathogens that are critical threats to the Warfighter. Less