title: Recruitment of Factor H to the Streptococcus suis Cell Surface is Multifactorial.
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.
authors.affiliation: Research 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.
authors.forename: David
authors.initials: D
authors.lastname: Roy
authors.affiliation: Oral Ecology Research Group, Faculty of Dentistry, Laval University, Quebec City, J2S 7C6, Quebec, Canada. Daniel.Grenier@greb.ulaval.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Grenier
authors.affiliation: Research 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. mariela.segura@umontreal.ca.
authors.forename: Mariela
authors.initials: M
authors.lastname: Segura
authors.affiliation: Research 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. annabelle.mathieu-denoncourt@umontreal.ca.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Mathieu-Denoncourt
authors.affiliation: Research 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. marcelo.gottschalk@umontreal.ca.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
keywords: C3b; Streptococcus suis; adhesion; complement; factor H; factor H-binding proteins; phagocytosis; polysaccharide capsule