Location: Foreign Arthropod Borne Animal Disease Research
Project Number: 3022-32000-025-016-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2022
End Date: Aug 31, 2025
Japanese encephalitis virus (JEV) represents a significant zoonotic threat to the United States and there are no approved JEV vaccines for domestic use in swine, the key amplifying host of the virus. Further, emerging genotypes of JEV and expansion of their geographic range warrant the development of new vaccines that can protect against all JEV genotypes. The development of these vaccines will aid in control measures of JEV to prevent amplification of JEV in swine. The cooperator has developed a novel virus-like particle (VLP) vaccine platform that is broadly applicable to numerous arthropod-borne viruses (arboviruses) including dengue, JEV, West Nile and Zika and a patent covering the vaccine platform was recently granted by the United States Patent and Trade Office. To date, the cooperator has developed dengue and ZIKV VLP vaccine candidates and the ZIKV VLP demonstrated significant efficacy when tested in vivo using a neurovirulent model of disease. The cooperator would apply their technology to JEV and generate recombinant vaccine candidates for numerous JEV genotypes. The technology is scalable as demonstrated by upstream and downstream manufacturing processes piloted by the cooperator for their dengue and Zika VLP vaccine candidates and it is anticipated that the cooperator would pilot these processes for JEV vaccine candidates as well. The cooperator also has access to numerous isolates of JEV, including a genotype V virus, which will be important for evaluating neutralizing antibodies generated by JEV vaccine candidates in vivo and for using as a challenge virus in vaccine efficacy trials in vivo. Further, the cooperator has numerous monoclonal antibodies that bind JEV envelope and nonstructural protein in house that can be used to develop JEV vaccine identity and potency assay, which will be key for product development. The objectives of this collaboration are to create novel vaccine candidates for each JEV genotype and evaluate their immunogenicity, through construction of JEV VLP expression cassettes for 5 different genotypes (I-V) that are codon optimized for human and insect cell expression and optimize their yield.
The cooperator has developed a novel virus-like particle (VLP) vaccine platform that is broadly applicable to numerous arthropod-borne viruses including dengue, JEV, West Nile and Zika (ZIKV) and a patent covering the vaccine platform was recently allowed by the United States Patent and Trade Office. To date, the cooperator has developed dengue and ZIKV VLP vaccine candidates and the ZIKV VLP demonstrated significant efficacy when tested in vivo using a neurovirulent model of disease. The technology is scalable as demonstrated by the manufacturing processes piloted by the cooperator for the dengue and ZIKV VLP vaccine candidates. Using the patented VLP vaccine platform, expression cassettes will be constructed for all five JEV genotypes. A complete expression profile of each in human and insect cells will be determined and VLPs will be purified using tangential flow filtration and density ultracentrifugation. The VLP yield will be determined and the biochemical properties of the JEV VLP vaccine candidates will be characterized. As part of these studies, identity and quality control assays for JEV VLPs using existing in-house antigens and will be characterized JEV-specific monoclonal antibodies (mAbs) will be developed. In partnership with the USDA, JEV VLP immunogenicity studies will be completed in mice. If JEV VLP immunogenicity is poor, an additional vaccine component will be made. Specifically, a JEV nonstructural protein 1 (NS1) expression cassette will be constructed to produce JEV NS1 as an additional vaccine component. Initially only one genotype will be examined and JEV NS1 will be characterized and purified from human and insect cells and immunogenicity studies in mice will be repeated. Stable cell lines expressing human JEV VLP cassettes or highly purified recombinant baculoviruses expressing insect JEV VLP cassettes will be generated. Upstream processes in human or insect expression systems will be optimized to maximize JEV VLP yield. Downstream processes in human or insect expression systems will be developed to remove the need for density ultracentrifugation. Similar processes will be completed for JEV NS1 necessary. The goal of the project is to have sufficient amounts of purified JEV VLPs available by the end of the second year to complete pilot immunogenicity/efficacy studies in swine in partnership with the USDA. In the remaining years, dose and adjuvant will be evaluated in more detail and in various combinations. In addition, existing in-house antigens and JEV-specific mAbs will be used to design and develop serological assays to distinguish vaccinated and infected animals. Industry leaders will be engaged to establish collaboration and access to propriety swine adjuvants. Further, if efficacy studies are successful, licensing agreements with industry partners will be explored and the JEV vaccine platform technology will be transferred accordingly. Working with industry partners, and with standard input from the USDA, a regulatory strategy for JEV VLP vaccine candidates will be developed. If successful, a marketing strategy will also be developed to engage and educate stake holders.