Title |
Dectin-2-dependent host defense in mice infected with serotype 3 Streptococcus pneumoniae
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Published in |
BMC Immunology, January 2016
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DOI | 10.1186/s12865-015-0139-3 |
Pubmed ID | |
Authors |
Yukiko Akahori, Tomomitsu Miyasaka, Masahiko Toyama, Ikumi Matsumoto, Anna Miyahara, Tong Zong, Keiko Ishii, Yuki Kinjo, Yoshitsugu Miyazaki, Shinobu Saijo, Yoichiro Iwakura, Kazuyoshi Kawakami |
Abstract |
Streptococcus pneumoniae, a major causative bacterial pathogen of community-acquired pneumonia, possesses a thick polysaccharide capsule. Host defense against this bacterium is mediated by activation of innate immune cells that sense bacterial components. Recently, C-type lectin receptors (CLRs) have garnered much attention in elucidating the recognition mechanism of pathogen-derived polysaccharides. In the present study, we first compared the clinical course and neutrophil accumulation in the lungs of Dectin-2 knock-out (KO) and wild type (WT) mice. Mice were infected intratracheally with a serotype 3 strain of S. pneumoniae, and S. pneumoniae bacterial engulfment by neutrophils and inflammatory cytokine and anti-pneumococcal polysaccharide-specific IgG levels were evaluated in bronchoalveolar lavage fluid (BALF). We also examined the effect of Dectin-2 deficiency on interleukin (IL)-12 production by bone marrow-derived dendritic cells (BM-DCs) stimulated with the bacterial components. S. pneumonia-infected Dectin-2KO mice had a shorter survival time, larger bacterial burden and lower interferon gamma (IFN-γ) production in the lungs than WT mice. Although neutrophilic infiltration in the lungs was equivalent between Dectin-2KO mice and WT mice, S. pneumonia engulfment by neutrophils was attenuated in Dectin-2KO mice compared to WT mice. The anti-pneumococcal polysaccharide-specific IgG and IgG3 levels in BALF were lower in Dectin-2KO mice than in WT mice. When BM-DCs were stimulated with S. pneumoniae culture supernatant or its Concanavalin A (ConA)-bound fraction, IL-12 production was abrogated in Dectin-2KO mice compared to WT mice. We demonstrated that Dectin-2 is intimately involved in the host defense against infection with a serotype 3 strain of S. pneumoniae. Dectin-2-dependent IL-12 production may contribute to IFN-γ synthesis and subsequent production of serotype-specific anti-capsular polysaccharide IgG after S. pneumoniae infection, which may promote S. pneumoniae bacterial opsonization for engulfment. |
X Demographics
Geographical breakdown
Country | Count | As % |
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United Kingdom | 1 | 50% |
Unknown | 1 | 50% |
Demographic breakdown
Type | Count | As % |
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Science communicators (journalists, bloggers, editors) | 1 | 50% |
Members of the public | 1 | 50% |
Mendeley readers
Geographical breakdown
Country | Count | As % |
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Unknown | 30 | 100% |
Demographic breakdown
Readers by professional status | Count | As % |
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Student > Ph. D. Student | 6 | 20% |
Student > Bachelor | 5 | 17% |
Researcher | 4 | 13% |
Other | 2 | 7% |
Student > Postgraduate | 2 | 7% |
Other | 6 | 20% |
Unknown | 5 | 17% |
Readers by discipline | Count | As % |
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Immunology and Microbiology | 11 | 37% |
Biochemistry, Genetics and Molecular Biology | 3 | 10% |
Agricultural and Biological Sciences | 3 | 10% |
Medicine and Dentistry | 3 | 10% |
Computer Science | 1 | 3% |
Other | 3 | 10% |
Unknown | 6 | 20% |