Streptococcus pneumoniae is the leading cause of bacterial meningitis. Pneumococcal meningitis is a life-threatening disease with high rates of mortality and neurological sequelae. Immune targeting of S. pneumoniae is essential for clearance of infection; however, within the brain, the induced inflammatory response contributes to pathogenesis. In this study we investigate the local inflammatory response and the role of IFN-γ in a murine model of pneumococcal meningitis induced by intracranial injection of type 4 S. pneumoniae. Lymphoid and myeloid cell populations involved in meningitis, as well as cytokine gene expression, were investigated after infection. Animals were treated with a monoclonal antibody specific for murine IFN-γ to evaluate its role in animal survival. Intracranial inoculation of 3 × 104 colony-forming units of type 4 strain TIGR4 caused 75% of mice to develop meningitis within 4 days. The amount of lymphocytes, NK cells, neutrophils, monocytes and macrophages in the brain increased 48 h post infection. IFN-γ mRNA levels were about 240-fold higher in brains of infected mice compared to controls. Pro-inflammatory cytokines such as IL-1β and TNF-α, and TLR2 were also upregulated. In vivo treatment with anti-IFN-γ antibody increased survival of infected mice. This study shows that IFN-γ produced during meningitis by type 4 S. pneumoniae enhances bacterial pathogenesis exerting a negative effect on the disease outcome. © 2015 Pettini, Fiorino, Cuppone, Iannelli, Medaglini and Pozzi.

Pettini, E., Fiorino, F., Cuppone, A.M., Iannelli, F., Medaglini, D., Pozzi, G. (2015). Interferon-γ from Brain Leukocytes Enhances Meningitis by Type 4 Streptococcus pneumoniae. FRONTIERS IN MICROBIOLOGY, 6(1340), 1-9 [10.3389/fmicb.2015.01340].

Interferon-γ from Brain Leukocytes Enhances Meningitis by Type 4 Streptococcus pneumoniae

PETTINI, ELENA;FIORINO, FABIO;CUPPONE, ANNA MARIA;IANNELLI, FRANCESCO;MEDAGLINI, DONATA;POZZI, GIANNI
2015-01-01

Abstract

Streptococcus pneumoniae is the leading cause of bacterial meningitis. Pneumococcal meningitis is a life-threatening disease with high rates of mortality and neurological sequelae. Immune targeting of S. pneumoniae is essential for clearance of infection; however, within the brain, the induced inflammatory response contributes to pathogenesis. In this study we investigate the local inflammatory response and the role of IFN-γ in a murine model of pneumococcal meningitis induced by intracranial injection of type 4 S. pneumoniae. Lymphoid and myeloid cell populations involved in meningitis, as well as cytokine gene expression, were investigated after infection. Animals were treated with a monoclonal antibody specific for murine IFN-γ to evaluate its role in animal survival. Intracranial inoculation of 3 × 104 colony-forming units of type 4 strain TIGR4 caused 75% of mice to develop meningitis within 4 days. The amount of lymphocytes, NK cells, neutrophils, monocytes and macrophages in the brain increased 48 h post infection. IFN-γ mRNA levels were about 240-fold higher in brains of infected mice compared to controls. Pro-inflammatory cytokines such as IL-1β and TNF-α, and TLR2 were also upregulated. In vivo treatment with anti-IFN-γ antibody increased survival of infected mice. This study shows that IFN-γ produced during meningitis by type 4 S. pneumoniae enhances bacterial pathogenesis exerting a negative effect on the disease outcome. © 2015 Pettini, Fiorino, Cuppone, Iannelli, Medaglini and Pozzi.
Pettini, E., Fiorino, F., Cuppone, A.M., Iannelli, F., Medaglini, D., Pozzi, G. (2015). Interferon-γ from Brain Leukocytes Enhances Meningitis by Type 4 Streptococcus pneumoniae. FRONTIERS IN MICROBIOLOGY, 6(1340), 1-9 [10.3389/fmicb.2015.01340].
File in questo prodotto:
File Dimensione Formato  
2015 Pettini et al Frontiers in Microbiology.pdf

accesso aperto

Tipologia: PDF editoriale
Licenza: Creative commons
Dimensione 1.88 MB
Formato Adobe PDF
1.88 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/982067