Function of the Fibronectin-Binding Serum Opacity Factor ofStreptococcus pyogenesin Adherence to Epithelial Cells

Abstract
The serum opacity factor (SOF) ofStreptococcus pyogenesis a serotyping tool and pathogenesis factor. Using SOF-coated latex beads in cell adherence assays and antiserum directed against SOF inS. pyogenes-HEp-2 cell adherence inhibition experiments, we demonstrate SOF involvement in the fibronectin-mediated adherence ofS. pyogenesto epithelial cells. SOF exclusively targets the 30-kDa N-terminal region of fibronectin. The interaction revealed association and dissociation constants 1 order of magnitude lower than those of otherS. pyogenesfibronectin-binding proteins.