Binding of von Willebrand factor by coagulase-negative staphylococci

Coagulase-negative staphylococci (CNS) are the most common infectious micro organisms isolated from prosthetic devices. To determine whether von Willeb rand factor (vWF) acts as an adhesin in bacterial recognition, bacterial bi nding of recombinant vWF (rvWF) was studied. Eleven CNS strains, belonging to S. epidermidis, S. haemolyticus and S. hominis species, bound soluble rv WF, but to a lesser extent than S. aureus. S. epidermidis strain H2-W bound I-125-labelled rvWF in a dose-dependent manner. The binding could be inhib ited by unlabelled rvWF and thrombospondin, but not by fibrinogen, vitronec tin or the carbohydrates N-acetylgalactoseamine, D-galactose, D-glucose, an d D-fucose. Pre-incubation of rvWF with type I collagen and Arg-Gly-Asp-Ser (RGDS) peptides did not inhibit binding, whereas pre-incubation of rvWF wi th heparin decreased binding significantly. The interaction between CNS and rvWF was sensitive to proteinase treatment of bacterial cells. CNS strains bound to immobilised rvWF an extent greater or equal to the positive contr ol strain S. aureus Cowan I. rvWF binding structures from bacterial cell wa ll were detected by immunoblot. Cowan I strain had 140-, 90- and 38-kDa bin ding molecules. S. haemolyticus strain SM131 and S. epidermidis strain H2-W had two (120 and 60 kDa) and five (120, 90, 60, 52 and 38 kDa) binding mol ecules, respectively. Similar binding structures were formed when cell wall extracts from these strains were incubated with thrombospondin. These resu lts indicate that specific ligand-receptor interaction between CNS and rvWF may contribute to bacterial adhesion and colonisation on biomaterial surfa ces. Heparin-binding domains of rvWF might be the crucial regions for bacte rial attachment. rvWF and thrombospondin may recognise similar molecules in staphylococcal cell wall extracts.