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Role of Toll-like receptor 2 in recognition of Legionella pneumophila in a murine pneumonia model.
- Source :
-
Journal of medical microbiology [J Med Microbiol] 2007 Mar; Vol. 56 (Pt 3), pp. 305-312. - Publication Year :
- 2007
-
Abstract
- Legionella pneumophila is an intracellular organism and the major aetiological agent of Legionnaires' disease. Although recent progress has identified Toll-like receptors (TLRs) as receptors for recognition of pathogen-associated molecular patterns in a variety of micro-organisms, understanding the contribution of TLRs to the host response in L. pneumophila infection is still limited. This study examined the roles of TLR2 and TLR4 in murine L. pneumophila pneumonia and an in vitro infection model using bone-marrow-derived macrophages. TLR2-deficient mice, but not TLR4-deficient mice, demonstrated higher lethal sensitivity to pulmonary challenge with L. pneumophila than wild-type mice (P<0.05). Although no differences in pulmonary bacterial burden were observed among the mouse strains examined, lower values of macrophage inflammatory protein-2 (MIP-2), keratinocyte-derived cytokine and interleukin (IL)-6 and higher IL-12 levels were noted in lung homogenates of TLR2-deficient mice compared with the wild-type control and TLR4-deficient mice. Recruitment of inflammatory cells, particularly neutrophils, was severely disturbed in the lungs of TLR2-deficient mice. Reduced MIP-2 production was demonstrated in bone-marrow-derived macrophages from TLR2-deficient mice in response to live L. pneumophila and purified LPS of this strain, but not Escherichia coli LPS. These data highlight the involvement and importance of TLR2 in the pathogenesis of L. pneumophila pneumonia in mice. The results showed that TLR2-mediated recognition of Legionella LPS and subsequent chemokine-dependent cellular recruitment may be a crucial host innate response in L. pneumophila pneumonia.
- Subjects :
- Animals
Bronchoalveolar Lavage Fluid cytology
Bronchoalveolar Lavage Fluid immunology
Cells, Cultured
Chemokine CXCL2
Disease Models, Animal
Immunity, Innate
Interleukin-12 analysis
Interleukin-6 analysis
Legionella pneumophila genetics
Legionnaires' Disease microbiology
Legionnaires' Disease pathology
Lipopolysaccharides immunology
Lung immunology
Lung microbiology
Lung pathology
Macrophages immunology
Macrophages microbiology
Mice
Mice, Inbred C57BL
Mice, Knockout
Monokines analysis
Pneumonia, Bacterial microbiology
Pneumonia, Bacterial pathology
Toll-Like Receptor 2 genetics
Toll-Like Receptor 4 immunology
Legionella pneumophila immunology
Legionnaires' Disease immunology
Pneumonia, Bacterial immunology
Toll-Like Receptor 2 immunology
Subjects
Details
- Language :
- English
- ISSN :
- 0022-2615
- Volume :
- 56
- Issue :
- Pt 3
- Database :
- MEDLINE
- Journal :
- Journal of medical microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 17314358
- Full Text :
- https://doi.org/10.1099/jmm.0.46913-0