Date of Award

2020

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Microbiology and Immunology

Abstract

Virus cell-to-cell spread has been implicated in the establishment of persistent infection and has been shown to be involved in the transmission of antiviral resistant mutants. However, relatively little is known about how virus cell-to-cell spread impacts infection or the specific mechanisms by which cell-to-cell spread occurs. as such, this dissertation focused on investigating HCV cell-to-cell spread not only to learn more about this medically important virus, but also to determine the broader impact cell-to-cell spread has on viral infection dynamics, identify the cellular factors involved, and perhaps ultimately provide insight into antiviral strategies that might enhance the barrier to antiviral resistance. First, we used a combination of experimentation and mathematical modeling to quantify the kinetics of HCV cell-to-cell spread. These efforts dissected the contribution of cell-free versus cell-to-cell spread and revealed a dynamic interplay between these two modes of spread in which cell-free spread enhances cell-to-cell spread by seeding new areas of available expansion space. We also observed that the contribution of these two means of spread can change under different experimental conditions suggesting that modulating between spread mechanisms is one way the virus may adjust to different environmental conditions. Second, we used a targeted siRNa screening approach to identify host factors involved in cell-to-cell spread. Because some of the genes involved in cell-to-cell spread are also involved in the assembly and secretion of cell-free virus while others are not, these data suggest that the pathways utilized for cell-free and cell-to-cell spread initially overlap but then diverge in the Golgi. While additional follow-up will be required to completely define the major mechanism of HCV cell-to-cell spread, we have identified specific cellular pathways involved and have evidence that HCV spreads at least in part via tunneling nanotubes (TNT), a mechanism implicated in the spread of numerous other viruses. in summary, this dissertation has provided new insight regarding the dynamics of HCV spread and identified specific cellular factors/pathways involved revealing clues about the molecular mechanisms of HCV cell-to-cell spread as well as providing new antiviral targets which may minimize antiviral escape.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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