The Role of MFS Family Transporters in the Lifecycle of Type A Francisella tularensis and Their Viability as Vaccine Targets
Başlık:
The Role of MFS Family Transporters in the Lifecycle of Type A Francisella tularensis and Their Viability as Vaccine Targets
Yazar:
Balzano, Phillip Mario Jan, author.
ISBN:
9780438028715
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (198 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-10(E), Section: B.
Advisors: Eileen M. Barry Committee members: Robert Ernst; David Rasko; Terez Shea-Donohue; Stefanie Vogel.
Özet:
Francisella tularensis is a Gram negative facultative intracellular coccobacillus that can infect a wide variety of hosts. In humans, F. tularensis causes the zoonosis tularemia following insect bites, ingestion, inhalation, and handling infected animals. That a small inoculum delivered by the aerosol route can cause severe disease, coupled with the possibility of its use as an aerosolized bioweapon, have led to the classification of Francisella tularensis as a Tier 1 Category A select agent and has renewed interest in vaccine formulation. To this end, this study aimed to engineer and evaluate novel F. tularensis strain SchuS4 derivatives containing single deletions of major facilitator superfamily (MFS) transporters fptG, fptE, fptF, and fptB. Additionally, these strains developed for vaccine purposes were utilized to study more intimately aspects of the intracellular lifecycle of F. tularensis..
Alterations to the intracellular lifecycle of the bacterium were measured using intracellular survival assays in multiple cell types. Two strains, F. tularensis SchuS4DeltafptB and SchuS4Delta fptG, displayed lifecycle alterations. Further analysis with these two strains involved characterization of the early inflammatory immune response from macrophages using ELISAs for cytokine secretion, and measuring alterations to host cell permeability by measuring supernatant lactate dehydrogenase release. In addition to in vitro analysis, F. tularensis strains SchuS4DeltafptB and SchuS4DeltafptG were evaluated for attenuation, and later, protective capacity, in vivo in the C57BL/6J mouse model.
In vitro studies demonstrated that F. tularensis strains SchuS4DeltafptB and SchuS4Delta fptG were significantly altered in their intracellular lifecycle, exhibiting a novel cytosolic escape delay phenotype that was found to be autophagy-dependent for SchuS4DeltafptG. Additionally, F. tularensis strain SchuS4DeltafptB exhibited a significant replication defect. Moreover, we observed prominent differences in in vitro cytokine profiles in human and mouse macrophages for both mutants. Both mutants were attenuated in the C57BL/6J mouse model, and one strain, SchuS4DeltafptB, provided partial protection against virulent Type A F. tularensis challenge. These results demonstrate a fundamental necessity for these nutrient transporters in the timely progression of F. tularensis through its replication cycle, and in pathogenesis. Collectively, these strains validate the strategy of targeting transporters as means of attenuation for F. tularensis vaccine strain construction.
Notlar:
School code: 0373
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(678166.1) | 678166-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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