ADVANCING FILOVIRUS VACCINE DEVELOPMENT: DEVELOPING HIGH-YIELD PLATFORMS TO EXPRESS AND PURIFY MARBURG VIRUS GLYCOPROTEIN AND OTHER VACCINE TARGETS

Abstract

This dissertation focuses on the advancement of recombinant subunit vaccine platforms through the optimized production, purification, and stability testing of a filovirus vaccine candidate. Filoviruses, including Ebola and Marburg virus, represent substantial global health threats due to their high lethality and almost annual recurrence of outbreaks. Since our world has become more and more connected, these outbreaks are not only limited to filovirus-endemic countries but have been occurring on a global scale, reaching countries at a far distance from endemicity, including Germany and the U.S. Although approved vaccines for Ebola virus are available, no approved vaccines exist for other filoviruses, including Marburg virus. Additionally, current vaccines are limited by cold-chain requirements, emphasizing the need for new vaccine platforms for the prevention of filovirus disease. This research aimed to (1) Increase the production of Marburg virus glycoprotein by testing novel expression vectors together with transposases and integrases, (2) develop cost-effective production of antibodies, including MARV GP-specific monoclonal antibody 9A11, for subsequent immunoaffinity purification. (3) evaluate the stability and immunogenicity of different filovirus vaccine formulations under extended storage at elevated temperatures. Our findings demonstrate significant improvements in protein production yields for MARV GP using our newly developed expression vectors, achieving MARV GP production levels suitable for large-scale vaccine manufacturing. We demonstrate the in-house production of multiple antibodies, including monoclonal 9A11, and confirm their ability to purify our vaccine antigens. Furthermore, our thermostability study demonstrates that lyophilized vaccine formulations retain immunogenicity after extended storage at elevated temperatures of 40°C for at least 2 years. Our findings show that our expression platform can produce robust and stable antigens. Together, our findings support a vaccine platform that can be formulated as thermostable, single-vial vaccines conducive to global distribution, including low- and middle-income countries in the Global South.