Structural and functional analysis of the Vaccinia virus O1 virulence protein
Weeks, Anastasia C.
Poxviruses are double-stranded DNA viruses capable of causing disfiguring and deadly disease in a wide range of hosts, from insects to mammals. Orthopoxviruses (OPXV) encode many proteins that are not essential for viral replication, but are responsible for vast differences in pathogenesis. Of the>200 proteins in the prototypical OPXV vaccinia virus (VACV), many remain functionally cryptic. The objective of these studies was to understand how the VACV O1 protein functions by investigating cell-specific effects that may contribute to virulence. The O1L gene is expressed early as the O1 protein, a 78 kDa protein that lacked N-linked glycosylation. These data are the first to demonstrate the reduced ability of an O1 deletion mutant ([delta]O1) to induce cell migration compared to the parental VACV Western Reserve strain (VACV-WR). [delta]O1-infected cell monolayers also exhibited reduced plaque diameter and clearance in plaque foci. These observations indicated that O1 is a significant contributor to VACV cytopathic effects (CPE) in vitro, in agreement with published reports. The results reported herein are the first to describe an altered immunological response with [delta]O1, as levels of anti-VACV immunoglobulin significantly increased with [delta]O1 infection at a time point (seven days post-infection) when VACV-WR induced VACV-specific antibody levels were comparable to sera from mock-infected mice. [delta]O1 was more immunogenic in an ex vivo antigen presentation assay, although mitogen-induced CD4+ T cell activation during [delta]O1 infection was equivalent to VACV-WR infection. Surprisingly, of all the immune cell types tested, [delta]O1 significantly differed from VACV-WR infection in the metabolic readout of only one cell type - RAW 264.7 macrophages. VACV-WR infected RAW 264.7 macrophages were more metabolically active than [delta]O1-infected cells at higher infectious doses, which may be indicative of a specialized niche for O1 function. Taken together, these data may provide clues into the mechanism of O1 virulence.
Weeks, Anastasia C.. (July 2017). Structural and functional analysis of the Vaccinia virus O1 virulence protein (Master's Thesis, East Carolina University). Retrieved from the Scholarship. (http://hdl.handle.net/10342/6393.)
Weeks, Anastasia C.. Structural and functional analysis of the Vaccinia virus O1 virulence protein. Master's Thesis. East Carolina University, July 2017. The Scholarship. http://hdl.handle.net/10342/6393. September 19, 2020.
Weeks, Anastasia C., “Structural and functional analysis of the Vaccinia virus O1 virulence protein” (Master's Thesis., East Carolina University, July 2017).
Weeks, Anastasia C.. Structural and functional analysis of the Vaccinia virus O1 virulence protein [Master's Thesis]. Greenville, NC: East Carolina University; July 2017.
East Carolina University