Streptococcus pneumoniae induces expression of the antibacterial CXC chemokine MIG/CXCL9 via MyD88-dependent signaling in a murine model of airway infection.
MIG/CXCL9 belongs to the CXC family of chemokines and participates in the regulation of leukocyte-trafficking and angiogenesis. Certain chemokines, including human MIG/CXCL9, exert strong antibacterial activity in vitro, although the importance of this property in vivo is unknown. In the present study, we investigated the expression and a possible role for MIG/CXCL9 in host defense during mucosal airway infection caused by Streptococcus pneumoniae in vivo. We found that intranasal challenge of C57BL/6 wild-type mice with pneumococci elicited production of high levels of MIG/CXCL9 in the lungs via the MyD88-dependent signaling pathway. Whereas both human and murine MIG/CXCL9 showed efficient killing of S. pneumoniae in vitro, MIG/CXCL9 knock-out mice were not more susceptible to pneumococcal infection. Our data demonstrate that, in vivo this chemokine probably has a redundant role, acting together with other antibacterial peptides and chemokines, in innate and adaptive host defense mechanisms against pneumococcal infections.
Eliasson
Mette
M
Lund University and Lund University Hospital, Department of Clinical Sciences, Section for Respiratory Medicine, and Allergology, Lund, Sweden.
Mörgelin
Matthias
M
Farber
Joshua M
JM
Egesten
Arne
A
Albiger
Barbara
B
D000818:Animals; D000890:Anti-Infective Agents / Q000378:metabolism*; D054370:Chemokine CXCL9 / Q000378:metabolism*; D004195:Disease Models, Animal; D054884:Host-Pathogen Interactions; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008168:Lung / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism*; D011018:Pneumonia, Pneumococcal / Q000276:immunology / Q000378:metabolism*; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction; D013296:Streptococcus pneumoniae / Q000502:physiology*
D000890:Anti-Infective Agents; C111954:CXC chemokine Mig; D054370:Chemokine CXCL9; D053594:Myeloid Differentiation Factor 88; D007371:Interferon-gamma