TLR-dependent control of Francisella tularensis infection and host inflammatory responses

Allison L. Abplanalp, Ian R. Morris, Bijaya K. Parida, Judy M. Teale, Michael T Berton

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Background: Francisella tularensis is the causative agent of tularemia and is classified as a Category A select agent. Recent studies have implicated TLR2 as a critical element in the host protective response to F. tularensis infection, but questions remain about whether TLR2 signaling dominates the response in all circumstances and with all species of Francisella and whether F. tularensis PAMPs are predominantly recognized by TLR2/TLR1 or TLR2/TLR6. To address these questions, we have explored the role of Toll-like receptors (TLRs) in the host response to infections with F. tularensis Live Vaccine Strain (LVS) and F. tularensis subspecies (subsp.) novicida in vivo. Methodology/Principal Findings: C57BL/6 (B6) control mice and TLR- or MyD88-deficient mice were infected intranasally (i.n.) or intradermally (i.d.) with F. tularensis LVS or with F. tularensis subsp. novicida. B6 mice survived >21 days following infection with LVS by both routes and survival of TLR1-/-, TLR4-/-, and TLR6-/- mice infected i.n. with LVS was equivalent to controls. Survival of TLR2-/- and MyD88-/ - mice, however, was significantly reduced compared to B6 mice, regardless of the route of infection or the subspecies of F. tularensis. TLR2-/- and MyD88-/- mice also showed increased bacterial burdens in lungs, liver, and spleen compared to controls following i.n. infection. Primary macrophages from MyD88-/- and TLR2-/- mice were significantly impaired in the ability to secrete TNF and other pro-inflammatory cytokines upon ex vivo infection with LVS. TNF expression was also impaired in vivo as demonstrated by analysis of bronchoalveolar lavage fluid and by in situ immunofluorescent staining. Conclusions/Significance: We conclude from these studies that TLR2 and MyD88, but not TLR4, play critical roles in the innate immune response to F. tularensis infection regardless of the route of infection or the subspecies. Moreover, signaling through TLR2 does not depend exclusively on TLR1 or TLR6 during F. tularensis LVS infection.

Original languageEnglish (US)
Article numbere7920
JournalPLoS One
Volume4
Issue number11
DOIs
StatePublished - Nov 20 2009

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Francisella tularensis
Tularemia
Toll-Like Receptors
Vaccines
inflammation
live vaccines
mice
infection
Infection
Francisella
Macrophages
Francisella tularensis subsp. novicida
Liver
tularemia
Toll-like receptors
Bronchoalveolar Lavage Fluid
Innate Immunity
Cytokines
Fluids
Spleen

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

TLR-dependent control of Francisella tularensis infection and host inflammatory responses. / Abplanalp, Allison L.; Morris, Ian R.; Parida, Bijaya K.; Teale, Judy M.; Berton, Michael T.

In: PLoS One, Vol. 4, No. 11, e7920, 20.11.2009.

Research output: Contribution to journalArticle

Abplanalp, Allison L. ; Morris, Ian R. ; Parida, Bijaya K. ; Teale, Judy M. ; Berton, Michael T. / TLR-dependent control of Francisella tularensis infection and host inflammatory responses. In: PLoS One. 2009 ; Vol. 4, No. 11.
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AU - Berton, Michael T

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