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A Francisella tularensis live vaccine strain that improves stimulation of antigen-presenting cells does not enhance vaccine efficacy

Schmitt, DM and O'Dee, DM and Horzempa, J and Carlson, PE and Russo, BC and Bales, JM and Brown, MJ and Nau, GJ (2012) A Francisella tularensis live vaccine strain that improves stimulation of antigen-presenting cells does not enhance vaccine efficacy. PLoS ONE, 7 (2).

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Vaccination is a proven strategy to mitigate morbidity and mortality of infectious diseases. The methodology of identifying and testing new vaccine candidates could be improved with rational design and in vitro testing prior to animal experimentation. The tularemia vaccine, Francisella tularensis live vaccine strain (LVS), does not elicit complete protection against lethal challenge with a virulent type A Francisella strain. One factor that may contribute to this poor performance is limited stimulation of antigen-presenting cells. In this study, we examined whether the interaction of genetically modified LVS strains with human antigen-presenting cells correlated with effectiveness as tularemia vaccine candidates. Human dendritic cells infected with wild-type LVS secrete low levels of proinflammatory cytokines, fail to upregulate costimulatory molecules, and activate human T cells poorly in vitro. One LVS mutant, strain 13B47, stimulated higher levels of proinflammatory cytokines from dendritic cells and macrophages and increased costimulatory molecule expression on dendritic cells compared to wild type. Additionally, 13B47-infected dendritic cells activated T cells more efficiently than LVS-infected cells. A deletion allele of the same gene in LVS displayed similar in vitro characteristics, but vaccination with this strain did not improve survival after challenge with a virulent Francisella strain. In vivo, this mutant was attenuated for growth and did not stimulate T cell responses in the lung comparable to wild type. Therefore, stimulation of antigen-presenting cells in vitro was improved by genetic modification of LVS, but did not correlate with efficacy against challenge in vivo within this model system. © 2012 Schmitt et al.


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Item Type: Article
Status: Published
CreatorsEmailPitt UsernameORCID
Schmitt, DM
O'Dee, DM
Horzempa, J
Carlson, PE
Russo, BC
Bales, JM
Brown, MJ
Nau, GJgjnau@pitt.eduGJNAU
ContributionContributors NameEmailPitt UsernameORCID
Date: 15 February 2012
Date Type: Publication
Journal or Publication Title: PLoS ONE
Volume: 7
Number: 2
DOI or Unique Handle: 10.1371/journal.pone.0031172
Schools and Programs: School of Medicine > Microbiology and Molecular Genetics
Refereed: Yes
MeSH Headings: Animals; Antigen-Presenting Cells--immunology; Bacterial Vaccines--administration & dosage; Cytokines--metabolism; Dendritic Cells--immunology; Dendritic Cells--metabolism; Dendritic Cells--virology; Female; Flow Cytometry; Francisella tularensis--genetics; Francisella tularensis--immunology; Francisella tularensis--pathogenicity; Humans; Immunization; Lung--immunology; Lung--metabolism; Lung--virology; Macrophages--immunology; Macrophages--metabolism; Macrophages--virology; Mice; Mice, Inbred C57BL; Monocytes--immunology; Monocytes--metabolism; Monocytes--virology; Tularemia--immunology; Tularemia--mortality; Tularemia--therapy; Vaccination; Vaccines, Attenuated--administration & dosage; Virulence
Other ID: NLM PMC3280287
PubMed Central ID: PMC3280287
PubMed ID: 22355343
Date Deposited: 13 Sep 2012 15:45
Last Modified: 02 Feb 2019 14:55


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