| Abstract: |
[Truncated abstract] The hepatitis C virus (HCV) is a significant human pathogen for which there are limited post-infection therapies and no effective vaccine. Research into HCV is notoriously difficult due to the absence of suitable in vitro and in vivo model systems with which to study the virus. Furthermore, our understanding of HCV host interaction is limited and the mechanisms by which it subverts the host immune system remains largely unknown. Due to the difficult nature associated with studying HCV, the work presented in this thesis was designed to addresses a broad range of issues relating to both clinical and molecular aspects of HCV. Chronic HCV infection is often associated with the development of cirrhosis, end stage liver disease and hepatocellular carcinoma. To date, histological examination of liver biopsies provides the only approved method with which to assess the level of liver damage. While clinically informative, liver biopsies are highly invasive and may be contraindicative for patients such as haemophiliacs. Cytokine specific ELISPOT assays were used to determine whether cytokine secretion from PBMCs isolated from chronically infected HCV patients could be used as a non-invasive method to assess liver damage. Chronically infected patients with sever liver fibrosis demonstrated a significantly reduced ability to produce IFN-γ in response to HCV Core, but not other unrelated antigens, indicating that decreased IFN-γ secretion by PBMCs in response to HCV antigen could be used as a non-invasive marker for the development of liver fibrosis ... A series of HCV expression vectors covering the full length of the HCV ORF were constructed and their expression extensively tested before being used to assess the ability of HCV proteins to interact with Jak/STAT mediated Type I IFN signalling. Additionally, an alternative set of HCV IRES-EGFP reporter vectors were developed and used to access HCV IRES functionality between different eukaryotic cell lines. HCV Core protein expressed alone or in concert with E1-P7 and non-structural protein NS5B were shown to significantly reduce Jak/STAT mediated IFN expression. While the influence of HCV Core on Type I IFN signalling is consistent with previous reports in the literature, these results identify a new role for NS5B as a possible candidate protein involved in inhibition of Type I IFN signalling. |
