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Mechanisms of Host-Pathogen Protein Complex Formation and Bacterial Immune Evasion of Streptococcus suis Protein Fhb
- Source :
- Journal of Biological Chemistry. 291:17122-17132
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- Streptococcus suis serotype 2 (S. suis 2)-induced sepsis and meningitis are often accompanied by bacteremia. The evasion of polymorphonuclear leukocyte-mediated phagocytic clearance is central to the establishment of bacteremia caused by S. suis 2 and is facilitated by the ability of factor H (FH)-binding protein (Fhb) to bind FH on the bacterial surface, thereby impeding alternative pathway complement activation and phagocytic clearance. Here, C3b/C3d was found to bind to Fhb, along with FH, forming a large immune complex. The formation of this immune complex was mediated by domain II of Fhb via electrostatic and hydrophobic interactions, which, to our knowledge, is a new type of interaction. Interestingly, Fhb was found to be associated with the cell envelope and also present in the culture supernatant, where secreted Fhb inhibited complement activation via interactions with domain II, thereby enhancing antiphagocytic clearance by polymorphonuclear leukocytes. Thus, Fhb is a multifunctional bacterial protein, which binds host complement component C3 as well as FH and interferes with innate immune recognition in a secret protein manner. S. suis 2 therefore appears to have developed a new strategy to combat host innate immunity and enhance survival in host blood.
- Subjects :
- 0301 basic medicine
Streptococcus suis
030106 microbiology
Biology
Microbiology
Biochemistry
03 medical and health sciences
Immune system
Bacterial Proteins
Immunity
Streptococcal Infections
Leukocytes
Humans
Molecular Biology
Immune Evasion
Innate immune system
Streptococcus suis serotype 2
Cell Biology
biology.organism_classification
Virology
Immune complex
Complement system
030104 developmental biology
Complement C3d
Complement Factor H
Complement C3b
Host-Pathogen Interactions
Alternative complement pathway
Subjects
Details
- ISSN :
- 00219258
- Volume :
- 291
- Database :
- OpenAIRE
- Journal :
- Journal of Biological Chemistry
- Accession number :
- edsair.doi.dedup.....e4d3e06aa17916129f0c1e66fa5dc6b6