Evasion of macrophage scavenger receptor A-mediated recognition by pathogenic streptococci
Författare
Summary, in English
PRR recognize conserved structures on pathogenic microbes and are important for the defense against invading microorganisms. However, accumulating evidence indicates that many pathogens have evolved mechanisms to avoid recognition by PRR. One type of PRR is the macrophage scavenger receptor A (SR-A), which has been shown to play an important role in recognition and non-opsonic phagocytosis of pathogenic bacteria. The bacterial ligands for SR-A have been suggested to be LPS or lipoteichoic acid. Here, we use murine bone marrow-derived macrophages to analyze the role of SR-A in non-opsonic phagocytosis of two major Gram-positive pathogens, streptococcus agalactiae (group B streptococcus; GBS) and Streptococcus pyogenes. We show that the polysaccharide capsule of GBS and the surface M protein of S. pyogenes, two important virulence factors, prevent SR-A-mediated non-opsonic phagocytosis of streptococci. The sialic acid moiety of the GBS capsule was crucial for its ability to prevent recognition by SR-A. Moreover, we show that a ligand on GBS recognized by SR-A in the absence of capsule is the surface lipoprotein BIr. These findings represent the first example of a microbial strategy to prevent recognition by SR-A and suggest that bacterial surface proteins may be of importance as ligands for SR-A.
Avdelning/ar
Publiceringsår
2008
Språk
Engelska
Sidor
3068-3079
Publikation/Tidskrift/Serie
European Journal of Immunology
Volym
38
Issue
11
Dokumenttyp
Artikel i tidskrift
Förlag
John Wiley & Sons Inc.
Ämne
- Immunology in the medical area
Nyckelord
- Scavenger receptor A
- Polysaccharide capsule
- M protein
- Macrophage
- streptococcus
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1521-4141