Theses and Dissertations

Jaime Rutter

Issuing Body

Mississippi State University

Advisor

Seo, Keun Seok

Committee Member

Pinchuk, Lesya

Committee Member

Pruett, Stephen

Committee Member

Thornton, Justin

Date of Degree

8-7-2020

Original embargo terms

Worldwide

Document Type

Dissertation - Open Access

Major

Veterinary Medical Science

Degree Name

Doctor of Philosophy

College

College of Veterinary Medicine

Department

Veterinary Medical Science Program

Abstract

Staphylococcus aureus employs an array of virulence factors to aid in its pathogenesis. A subset of cytotoxins termed bi-component leucocidins have been characterized as important determinants in the host-pathogen interaction in S. aureus infections. While they have been studied over a century, bi-component leucocidins’ complex mechanisms in pathogenesis have not been fully elucidated. Secreted as monomers, with the exception of LukAB/GH, many combinations of the S- (HlgA, HlgC, LukE, LukS, LukA/H) and F- (HlgB, LukD, LukF, LukB/G) components have demonstrated cell lysis via pore formation and a magnified proinflammatory response at sublytic concentrations. While studies have described various host cellular receptors and therapeutic strategies to evade leucocidin binding, a common receptor for all the leucocidins has yet to be classified. Challenges in data extrapolation have occurred due to non-native protein expression methods and species specificity of the leucocidin components. In turn, developing successful therapeutic strategies has proven problematic with a need for multimodal therapy. Thus, our studies aimed to clarify the bi-component leucocidins’ cytotoxic effects on multiple subsets of leukocytes using a native protein expression system and to identify a novel human leukocyte receptor common to all leucocidins. Overall, combinations with HlgA and LukE demonstrated the highest degrees of cytotoxicity against PMNs and PBMCs. Coronin 1A was discovered as a common receptor for all cognate pairs of bi-component leucocidins, except LukAB/GH. In conclusion, our results have expanded the knowledge of the cellular targets for leucocidin cytotoxicity and have described a common leucocidin receptor as a potential therapeutic target against the bi-component leucocidins.

URI

https://hdl.handle.net/11668/18465

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