Kupffer Cells In Action: Understanding The Mechanisms Of Hepadnaviral Persistence

Al-Yasiri, Layla

Kupffer Cells In Action: Understanding The Mechanisms Of Hepadnaviral Persistence

dc.contributor.advisor	Coffin, Carla S.
dc.contributor.author	Al-Yasiri, Layla
dc.contributor.committeemember	Jenne, Craig N.
dc.contributor.committeemember	van der Meer, Frank
dc.date	2023-11
dc.date.accessioned	2023-07-20T17:17:00Z
dc.date.available	2023-07-20T17:17:00Z
dc.date.issued	2023-06
dc.description.abstract	Hepatitis B virus (HBV) is the prototypical member of Hepadnaviridae family, and a causative agent of liver disease. Despite the availability of a vaccine, an estimated 1.5 million new individuals become infected each year. HBV can establish persistent infection in hepatocytes, which can disrupt hepatic homeostasis. Kupffer cells (KCs) are liver-resident macrophages that act as the first of line of defense against infectious agents. Woodchuck hepatitis virus (WHV) is a member of Hepadnaviridae. North American woodchucks (Marmota monax) infected with WHV present a natural immunocompetent model and demonstrate comparable infection outcomes and progression to hepatocellular carcinoma. We hypothesized that KC absence in acute viral hepatitis leads to chronicity by impacting virus processing and immune responses. To investigate this, we sought to uncover the early host-virus interactions in acute WHV infection. We designed and optimized in-house WHV and woodchuck-specific assays to assess intrahepatic and systemic virus presence following WHV challenge (<24 hours) and infection (6 weeks). An intravital imaging protocol was developed to capture real-time events in a living woodchuck using purified and fluorescently labelled WHV. Clodronate liposome-mediated depletion of KCs in woodchucks was performed to evaluate pre-acute challenge and acute infection in either the presence or absence of KCs. Intravital imaging of woodchucks challenged with WHV showed first appearance of virus in the liver within 30 seconds and capture by KCs within 5-10 minutes. In addition, depletion of KCs did not impact the localization of WHV during the initial hour or 24 hours of challenge. Assessment of WHV markers, serology and liver histology revealed differences in viral and biochemical markers between the KC-depleted and non-depleted animals over the initial 6 weeks. KC depletion, prior to acute WHV infection, resulted in faster onset of acute hepatitis (elevated liver enzymes) and greater suppression of WHV DNA (in circulation and intrahepatically). However, there was no difference in WHV DNA suppression between KC-depleted and non-depleted cohorts after 6 weeks p.i, as all assayed woodchucks achieved suppression of plasma WHV DNA. This may suggest that KCs normally operate under tolerogenic conditions to prevent hepatocyte damage and hepatitis, allowing for greater viral replication and immune evasion.
dc.identifier.citation	Al-Yasiri, L. (2023). Kupffer cells in action: understanding the mechanisms of Hepadnaviral persistence (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/116766
dc.identifier.uri	https://dx.doi.org/10.11575/PRISM/41608
dc.language.iso	en
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Woodchuck Hepatitis Virus (WHV)
dc.subject	Hepatitis B Virus (HBV)
dc.subject	Hepadnavirus
dc.subject	Kupffer Cells
dc.subject	Innate Immunity
dc.subject	Intravital Microscopy (IVM)
dc.subject.classification	Microbiology
dc.subject.classification	Immunology
dc.title	Kupffer Cells In Action: Understanding The Mechanisms Of Hepadnaviral Persistence
dc.type	master thesis
thesis.degree.discipline	Medicine – Microbiology & Infectious Diseases
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)
ucalgary.thesis.accesssetbystudent	I require a thesis withhold – I need to delay the release of my thesis due to a patent application, and other reasons outlined in the link above. I have/will need to submit a thesis withhold application.