Related Experiment Video
Updated: Mar 18, 2026
Cell Surface Receptor Identification Using Genome-Scale CRISPR/Cas9 Genetic Screens
Published on: June 6, 2020
Recruitment of Factor H to the Streptococcus suis Cell Surface is Multifactorial
David Roy1, Daniel Grenier2, Mariela Segura3
1Research Group on Infectious Diseases in Production Animals and Swine and Poultry Infectious Diseases Research Centre, Faculty of Veterinary Medicine, University of Montreal, Saint-Hyacinthe, J2S 7C6, Quebec, Canada. david.roy.6@umontreal.ca.
Abstract:
Streptococcus suis is an important bacterial swine pathogen and a zoonotic agent. Recently, two surface proteins of S. suis, Fhb and Fhbp, have been described for their capacity to bind factor H-a soluble complement regulatory protein that protects host cells from complement-mediated damages. Results obtained in this study showed an important role of host factor H in the adhesion of S. suis to epithelial and endothelial cells. Both Fhb and Fhbp play, to a certain extent, a role in such increased factor H-dependent adhesion. The capsular polysaccharide (CPS) of S. suis, independently of the presence of its sialic acid moiety, was also shown to be involved in the recruitment of factor H. However, a triple mutant lacking Fhb, Fhbp and CPS was still able to recruit factor H resulting in the degradation of C3b in the presence of factor I. In the presence of complement factors, the double mutant lacking Fhb and Fhbp was similarly phagocytosed by human macrophages and killed by pig blood when compared to the wild-type strain. In conclusion, this study suggests that recruitment of factor H to the S. suis cell surface is multifactorial and redundant.
Insights
Streptococcus suis uses multiple strategies, including surface proteins Fhb and Fhbp, and its capsular polysaccharide, to bind host factor H, aiding bacterial adhesion and immune evasion.
Area of Science:
- Bacteriology
- Immunology
- Zoonotic Diseases
Background:
- Streptococcus suis is a significant swine pathogen and zoonotic agent.
- Surface proteins Fhb and Fhbp of S. suis bind factor H, a complement regulator.
- Factor H protects host cells from complement-mediated damage.
Purpose of the Study:
- To investigate the role of host factor H in S. suis adhesion.
- To determine the contribution of Fhb, Fhbp, and capsular polysaccharide (CPS) to factor H binding and S. suis virulence.
Main Methods:
- Adhesion assays using epithelial and endothelial cells.
- Construction and analysis of S. suis mutants (Fhb, Fhbp, CPS single and triple mutants).
- Complement component C3b degradation assays in the presence of factor I.
- Phagocytosis assays with human macrophages and bacterial killing assays with pig blood.
Main Results:
- Host factor H significantly enhances S. suis adhesion to host cells.
- Fhb and Fhbp contribute to factor H-dependent adhesion, but are not solely responsible.
- S. suis capsular polysaccharide (CPS) also recruits factor H, independent of sialic acid.
- A triple mutant (lacking Fhb, Fhbp, and CPS) still recruits factor H and degrades C3b.
- The double mutant (lacking Fhb and Fhbp) exhibits similar phagocytosis and killing rates as the wild-type strain.
Conclusions:
- Factor H recruitment by S. suis is a multifactorial process.
- Redundant mechanisms ensure factor H binding to the S. suis surface.
- These findings highlight the complex immune evasion strategies of S. suis.
More Related Videos
07:26Intracranial Subarachnoidal Route of Infection for Investigating Roles of Streptococcus suis Biofilms in Meningitis in a Mouse Infection Model
Published on: July 1, 2018
13:11Super-Resolution Imaging of Bacterial Secreted Proteins Using Genetic Code Expansion
Published on: February 10, 2023
Related Concept Videos
01:01Regulation of Hematopoietic Stem Cells
01:19Mechanism of Conjugation
01:19Formation of Lipopolysaccharides