Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Microbiology and Immunology

Collaborative Specialization

Global Health Systems in Africa

Supervisor

Arts, Eric

2nd Supervisor

Dikeakos, Jimmy

Co-Supervisor

Abstract

Current vesicular stomatitis virus (VSV)-based HIV vaccines require an optimal HIV envelope immunogen to improve protection in vivo. Furthermore, the involvement of viral proteins, such as HIV Nef, in the trafficking of HIV Env to sites of viral assembly remains poorly understood and may provide additional insights for the design of a VSV-based HIV vaccine. We constructed new codon-optimized chimeric Env immunogens containing the signal sequence of honeybee melittin and the transmembrane and cytoplasmic tail domains of SIV, Zaire Ebola, or VSV glycoproteins. We showed that all chimeric Env immunogens had enhanced expression levels within producer cells. Utilizing bimolecular fluorescence complementation for intracellular protein-protein interactions, we identified a potential Env:Nef complex, which was disrupted by well-characterized Nef mutants. Overall, we have generated new highly expressing chimeric HIV-1 Env immunogens prepared for testing in the VSV vaccine platform and have shown evidence for a potential Env:Nef interaction within Env trafficking pathways.

Summary for Lay Audience

Over 36 million people suffer from Human Immunodeficiency Virus (HIV) and approximately 1.8 million new cases arise annually. While drugs exist to help treat symptoms, currently no vaccine is available to prevent and combat the prevalent spread of infections. We aimed to improve upon a vaccine designed by Dr. Chris Parks from the International AIDS Vaccine Initiative. This vaccine uses a modified animal virus (VSV), which does not cause disease in humans, as a vehicle to safely deliver a fragment of a surface protein from HIV termed Env. This HIV protein interacts with the body’s immune system to stimulate production of antibodies that protect against future HIV infection. We further improved and engineered the Env protein in multiple ways to enhance its protection abilities by increasing its presence within the VSV delivery vehicle. Eventually, we plan to test the efficacy of these new vaccines in mice and rabbits to select the best candidate. Finally, the most promising candidates will be tested in rhesus monkeys to see if they can protect these animals against a similar virus infection. In addition to improving the vaccine, we also studied the unaltered form of the Env protein to better understand how it functions within our cells. We have found evidence supporting a new interaction for Env protein, which has the potential to become novel targets for therapeutic strategies against HIV infections. Based on our future studies on Env protein vaccine implementation and function, we wish to use the knowledge from these studies to aid in humanity’s war to conquer HIV.

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