Thesis Format
Integrated Article
Degree
Master of Science
Program
Microbiology and Immunology
Supervisor
Creuzenet, Carole
2nd Supervisor
Arts, Eric
Co-Supervisor
Abstract
The extraordinary genetic diversity of HIV variants and their differences in glycosylation of surface protein gp120 have resulted in 30+ years of research with no universal vaccine. Despite this, most transmission events occur from a single transmitted founder virus (T/F). Glycan-binding proteins (lectins) are also thought to be important for HIV’s transmission. This study set out to analyze differences in gp120 glycosylation between T/F and chronic HIV strains using mass spectrometry, site-specific computational analyses, and lectin microarrays. Current results indicate gp120 glycosylation and lectin binding can differ significantly between strains, which may correlate with the differential transmission fitness of the strains. Ultimately, this study has unveiled site-specific patterns of glycosylation that can be investigated further as novel vaccine targets.
Summary for Lay Audience
HIV continues to be an enormous health burden worldwide despite 30+ years of research. The most significant obstacle in HIV vaccine development is HIV’s extraordinary ability to mutate and evolve, complicating the search for a universal vaccine effective against all viral variants. Despite its viral diversity, most new HIV infections are established by a singular viral strain, known as the transmitted founder virus (T/F). One of the major factors believed to contribute to the increased transmission fitness of T/F variants is the glycosylation of HIV’s surface glycoprotein (gp120). Glycosylation is a post-translational modification whereby sugar chains (glycans) are attached to proteins. Gp120 is crucial to viral transmission and gp120 glycosylation can work to shield the virus from the hosts’ immune response. Gp120 glycosylation can differ enormously between variants due to HIVs genetic variability. However, the differences in gp120 glycosylation between T/F variants and strains that develop during chronic infection are not well characterized.
This study set out to compare gp120s glycosylation between T/F and chronic strains using mass spectrometry (MS) and specialized glycoprotein analysis software synchronously. One T/F and one chronic strain were chosen as a proof of principle for this study. MS works by breaking gp120 into smaller fragments, which allows for the identification of glycans, peptides and glycopeptides. Software specialized to analyze MS glycoprotein data matches what was found experimentally to a list of theoretical glycopeptides. Data is then analyzed using novel bioinformatic pipelines developed specifically for this project. Gp120’s interactions with sugar-binding proteins (lectins), thought to be important for transmission, were also investigated using lectin microarray technology. For this project, the lectin microarray works by immobilizing lectins onto a slide and applying gp120 samples to understand differential lectin binding between strains. The findings of this thesis show that gp120 has significantly different glycosylation between strains and that lectin binding also differed significantly between strains.
This research addresses key knowledge gaps within HIV literature and will inform vaccine development on the differences in glycosylation between strains. The methodologies developed for this project can also be applied to the glycosylation of other pathogens in the future.
Recommended Citation
Temesy, Stephen, "Exploring New Methods to Dissect Site-Specific Differences in the N-glycosylation Patterns of HIV-1 Envelope Protein Gp120 in Chronic and Transmitted/Founder Virions" (2024). Electronic Thesis and Dissertation Repository. 10528.
https://ir.lib.uwo.ca/etd/10528
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
