Modulation of Innate Immune Cell Signaling Pathways by Staphylococcus aureus and Omnigen-AF®

dc.contributor.authorJohnson, Anne Caitlinen
dc.contributor.committeechairKanevsky, Isisen
dc.contributor.committeememberPetersson-Wolfe, Christina S.en
dc.contributor.committeememberXu, Binen
dc.contributor.departmentDairy Scienceen
dc.date.accessioned2015-05-03T06:00:31Zen
dc.date.available2015-05-03T06:00:31Zen
dc.date.issued2013-11-08en
dc.description.abstractStaphylococcus aureus causes chronic mastitis in bovines that is difficult to treat with current therapeutics. The goal of this research is to provide information about and improve innate immune responses to infection. Infection can result in host cell apoptosis or programmed cell death. Many pathogens can inhibit apoptosis; thereby acquiring a replicative niche, a reprieve from immune responses, and an escape from treatments. We hypothesize that S. aureus inhibits apoptosis in dendritic cells (DC). To investigate our hypothesis, DC were infected with live S. aureus (LSA), γ-irradiated S. aureus (ISA), or Streptococcus agalactiae (Strep ag.) for 2 hours. Stimulations of DC included ultraviolet light (UV) and lipoteichoic acid (LTA). Results indicate that γ-irradiated S. aureus can inhibit UV-induced apoptosis by upregulating LTA. This research provides information about S. aureus infections, but further research is needed to improve responses to this type of infection. One way to improve innate immune responses to infection is by supplementing bovines with OmniGen-AF®, a probiotic that restores neutrophil function during immunosuppression. To determine the mechanism by which OmniGen-AF® functions, wildtype, MyD88 KO, and TLR4 KO mice were fed either normal chow or supplemented with OmniGen-AF® for two weeks. Mice were immunosuppressed with dexamethasone and challenged with LTA. LTA overcame immunosuppression in a TLR4-depenent manner regardless of supplementation with OmniGen-AF®. Overall this research supplies knowledge about S. aureus inhibition of apoptosis in DC and S. aureus LTA activation of PMN regardless of immunosuppression or supplementation with OmniGen-AF®.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:1734en
dc.identifier.urihttp://hdl.handle.net/10919/51964en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectStaphylococcus aureusen
dc.subjectdendritic cellen
dc.subjectApoptosisen
dc.subjectOmniGen-AF®en
dc.subjectimmunosuppressionen
dc.subjectneutrophilen
dc.subjectMyD88en
dc.titleModulation of Innate Immune Cell Signaling Pathways by Staphylococcus aureus and Omnigen-AF®en
dc.typeThesisen
thesis.degree.disciplineDairy Scienceen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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