Development and application of a vaccinia virus based system to study viral proteins modulating interferon expression and interferon induced antiviral activities

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dc.contributor.authorArsenio, Janilyn
dc.contributor.examiningcommitteeGibson, Spencer (Biochemistry and Medical Genetics) Yang, Xi (Immunology) Severini, Alberto (Medical Microbiology) Barry, Michele (University of Alberta)en_US
dc.contributor.supervisorCao, Jingxin (Medical Microbiology)en_US
dc.date.accessioned2012-01-11T17:26:58Z
dc.date.available2012-01-11T17:26:58Z
dc.date.issued2008-07
dc.degree.disciplineMedical Microbiologyen_US
dc.degree.levelDoctor of Philosophy (Ph.D.)en_US
dc.description.abstractThe interferon (IFN) system is integral to antiviral innate immunity in vertebrate hosts. Inside a cell, viral pathogen associated molecular patterns (PAMPs) trigger the IFN response, comprised of IFN induction and an IFN-induced antiviral state. However, viruses have evolved strategies to counteract the IFN system. The E3 protein of vaccinia virus (VV), encoded by the E3L gene, impedes cytokine expression and suppresses the activation and function of antiviral proteins. Deletion of the E3L gene (VVΔE3L) produces an IFN sensitive mutant virus that is replication defective in most human cell lines. Due to the limited human cell lines available to support VVΔE3L replication, the capacity of E3 inhibition of human IFN-induced antiviral activities is not well defined. In this study, VVΔE3L was generated and characterized to facilitate the study of other viral IFN antagonists at modulating human IFN-induced antiviral responses. A human liver carcinoma cell line, Huh7, was found to support VVΔE3L replication. A comprehensive analysis of VVΔE3L IFN sensitivity revealed E3 inhibits all human type I and type II IFN-induced antiviral activities by modulation of the protein kinase R (PKR) pathway. Influenza non-structural protein 1 (NS1) is well-known to mediate the suppression of IFN induction and IFN action in influenza virus infections. However, the IFN antagonizing potential of influenza NS1 may be virus subtype and/or isolate specific. VVΔE3L was next applied as an expression vector to study influenza NS1 function in modulating IFN-induced antiviral activities and IFN induction in human cells. Recombinant viruses were generated to express influenza NS1 (from avian H5N1 and pandemic viruses 1918 pH1N1, 1968 pH3N2, and 2009 pH1N1) in replacement of E3. It was found that influenza NS1 inhibits human IFN-induced antiviral activity in a subtype and isolate specific manner. Moreover, influenza NS1 differentially regulates human IFN expression in a virus isolate-dependent manner. Altogether, this work highlights the potential of VVΔE3L as an excellent virus model system to study viral proteins modulating IFN expression and IFN-induced antiviral activities in human cells.en_US
dc.description.noteFebruary 2012en_US
dc.identifier.citationArsenio et al. Virology. 2008en_US
dc.identifier.urihttp://hdl.handle.net/1993/5068
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.rightsopen accessen_US
dc.subjectinterferonen_US
dc.subjectvacciniaen_US
dc.subjectE3en_US
dc.subjectinfluenzaen_US
dc.subjectNS1en_US
dc.titleDevelopment and application of a vaccinia virus based system to study viral proteins modulating interferon expression and interferon induced antiviral activitiesen_US
dc.typedoctoral thesisen_US
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