Toll-Like Receptor 9 Contributes to Defense against Acinetobacter baumannii Infection

Infect Immun. 2015 Oct;83(10):4134-41. doi: 10.1128/IAI.00410-15. Epub 2015 Aug 3.

Abstract

Acinetobacter baumannii is a common nosocomial pathogen capable of causing severe diseases associated with significant morbidity and mortality in impaired hosts. Pattern recognition receptors, such as the Toll-like receptors (TLRs), play a key role in pathogen detection and function to alert the immune system to infection. Here, we examine the role for TLR9 signaling in response to A. baumannii infection. In a murine model of A. baumannii pneumonia, TLR9(-/-) mice exhibit significantly increased bacterial burdens in the lungs, increased extrapulmonary bacterial dissemination, and more severe lung pathology compared with those in wild-type mice. Following systemic A. baumannii infection, TLR9(-/-) mice have significantly increased bacterial burdens in the lungs, as well as decreased proinflammatory cytokine and chemokine production. These results demonstrate that TLR9-mediated pathogen detection is important for host defense against the opportunistic pathogen Acinetobacter baumannii.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acinetobacter Infections / genetics
  • Acinetobacter Infections / immunology*
  • Acinetobacter Infections / microbiology
  • Acinetobacter Infections / pathology
  • Acinetobacter baumannii / genetics
  • Acinetobacter baumannii / immunology
  • Acinetobacter baumannii / physiology*
  • Animals
  • Cytokines / genetics
  • Cytokines / immunology
  • Disease Models, Animal
  • Humans
  • Lung / immunology
  • Lung / microbiology
  • Lung / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Toll-Like Receptor 9 / genetics
  • Toll-Like Receptor 9 / immunology*

Substances

  • Cytokines
  • Tlr9 protein, mouse
  • Toll-Like Receptor 9