Interaction of von Willebrand factor with Staphylococcus aureus

Intravascular infection due to Staphylococcus aureus requires colonization of subendothelium in the presence of shear forces. von Willebrand factor (VWF) is a large multimeric glycoprotein playing a key role in platelet adhesion to subendothelium. To determine whether VWF may also play a role in adhesion of S. aureus to endovascular sites, binding of VWF to S. aureus and adhesion of S. aureus to VWF-adsorbed substrates was examined. Binding isotherms revealed a dose-dependent reaction of purified VWF with S. aureus Cowan 1 as well as VWF binding to other S. aureus strains. On solid phase, VWF showed saturable adsorption kinetics to polymethylmethacrylate and promoted S. aureus adhesion up to 67-fold in a trypsin-sensitive reaction. Similar adhesion promotion was observed when recombinant VWF was used. These results show that VWF interacts with S. aureus in suspension and promotes S. aureus adhesion to surfaces, suggesting a role of VWF in the pathogenesis of intravascular S. aureus infections.