Host immune response in Salmonella carriers

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Abstract/Contents

Abstract
Host-adapted pathogens depend on their host for transmission and dissemination to new hosts. Salmonella enterica includes a plethora of serovars that cause host-adapted diseases in both livestock animals and humans, an example of which is Salmonella enterica serovar Typhi, the causative agent of typhoid fever. Epidemiological and mathematical modeling data indicate that a specific subset of infected hosts are responsible for the majority of disease transmission. Human typhoid carriers are a classic example of this subset, characterized by persistently infected yet asymptomatic individuals who transmit disease via the fecal oral route. The work contained in this thesis attempts to answer how carriers differ from other hosts, in particular how the host immune response in carriers allows those individuals to remain asymptomatic despite the large numbers of Salmonella in the gastrointestinal tract. We use a mouse model of persistent Salmonella infection wherein a subset of the infected hosts (super-shedders) are able to transmit disease to naive cage mates. Having characterized the development of the host immune response during chronic Salmonella infection, we identify an immune state unique to super-shedder hosts. The super-shedder immune phenotype consists of an active innate immune response with high frequency of neutrophils and serum Interleukin-6 and a suppressed adaptive T cell response with dampened cytokine responsiveness. Administration of Granulocyte colony stimulating factor to moderate-shedders is sufficient to phenocopy the blunted T cell responses of the super-shedder immune state demonstrating that neutrophils control the suppression of the adaptive T cell response. The super-shedder immune state also serves a functional purpose, protecting the host against antibiotic-driven dysbiosis. The microbiota and host-pathogen interactions together induce a unique state of tolerance in Salmonella carriers, potentially contributing to the transmission of the pathogen in the general population.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2013
Issuance monographic
Language English

Creators/Contributors

Associated with Gopinath, Smita
Associated with Stanford University, Department of Microbiology and Immunology.
Primary advisor Monack, Denise M
Thesis advisor Monack, Denise M
Thesis advisor Chien, Yueh-Hsiu
Thesis advisor Falkow, Stanley
Thesis advisor Galli, Stephen J
Thesis advisor Sonnenburg, Justin, 1973-
Advisor Chien, Yueh-Hsiu
Advisor Falkow, Stanley
Advisor Galli, Stephen J
Advisor Sonnenburg, Justin, 1973-

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Smita Gopinath.
Note Submitted to the Department of Microbiology and Immunology.
Thesis Thesis (Ph.D.)--Stanford University, 2013.
Location electronic resource

Access conditions

Copyright
© 2013 by Smita Gopinath
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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