The CXC chemokine MIG/CXCL9 is important in innate immunity against Streptococcus pyogenes.
Pharyngitis caused by Streptococcus pyogenes is one of the most common bacterial infections in humans and is also a starting point for invasive S. pyogenes infection. Here, we describe that tonsil fluid from patients with streptococcal pharyngitis contains high amounts of the interferon (IFN)-dependent CXC chemokine known as monokine induced by IFN- gamma (MIG)/CXCL9. Also in vitro, inflamed pharyngeal epithelium produced large amounts of MIG/CXCL9 in the presence of bacteria. The CXC chemokines MIG/CXCL9, IFN-inducible protein-10/CXCL10, and IFN-inducible T cell alpha -chemoattractant/CXCL11 all showed antibacterial activity against S. pyogenes, and inhibition of MIG/CXCL9 expression reduced the antibacterial activity at the surface of inflamed pharyngeal cells. S. pyogenes of the clinically important M1 serotype secrets the protein streptococcal inhibitor of complement (SIC), which inhibited the antibacterial activity of the chemokines. As exemplified by S. pyogenes pharyngitis, the data identify a novel innate defense mechanism against invasive bacteria on epithelial surfaces.
Egesten
Arne
A
Section for Respiratory Medicine, Department of Clinical Sciences, Lund University, Lund, Sweden. Arne.Egesten@med.lu.se
Eliasson
Mette
M
Johansson
Helena M
HM
Olin
Anders I
AI
Morgelin
Matthias
M
Mueller
Anja
A
Pease
James E
JE
Frick
Inga-Maria
IM
Bjorck
Lars
L
D002478:Cells, Cultured; D054357:Chemokine CXCL10; D054371:Chemokine CXCL11; D054370:Chemokine CXCL9; D019743:Chemokines, CXC / Q000378:metabolism* / Q000494:pharmacology; D004847:Epithelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D007113:Immunity, Innate; D014066:Palatine Tonsil / Q000378:metabolism; D010612:Pharyngitis / Q000378:metabolism / Q000382:microbiology; D010614:Pharynx / Q000166:cytology / Q000378:metabolism; D011994:Recombinant Proteins; D013290:Streptococcal Infections / Q000276:immunology* / Q000382:microbiology*; D013297:Streptococcus pyogenes / Q000187:drug effects
C114753:CXCL10 protein, human; C515202:CXCL11 protein, human; C080810:CXCL9 protein, human; D054357:Chemokine CXCL10; D054371:Chemokine CXCL11; D054370:Chemokine CXCL9; D019743:Chemokines, CXC; D011994:Recombinant Proteins