Binding of Fibronectin to SsPepO Facilitates the Development of Streptococcus suis Meningitis.

Abstract

SsPepO is an important virulence in Streptococcus suis. In this study, we showed that SsPepO contributes to the human fibronectin-mediated adherence ability of S. suis to human brain microvascular endothelial cells. The addition of an antifibronectin antibody or an arginine-glycine-aspartic acid peptide that blocks fibronectin binding to integrins significantly reduced adherence of the wild-type but not the SspepO mutant strain, indicating the importance of the SsPepO-fibronectin-integrin interaction for S. suis cellular adherence. By analyzing Evans blue extravasation in vivo, we showed that the interaction between SsPepO and human fibronectin significantly increased permeability of the blood-brain barrier. Furthermore, the SspepO mutant caused lower bacterial loads in the brain than wild-type S. suis in models of meningitis. These data demonstrate that SsPepO is a fibronectin-binding protein, which plays a contributing role in the development of S. suis meningitis.