Repeating Structures of the Major Staphylococcal Autolysin Are Essential for the Interaction with Human Thrombospondin 1 and Vitronectin

Abstract

Background: Adhesion of Gram-positive bacteria to host cells is facilitated by human thrombospondin 1 and vitronectin. Results: Repeating structures R1 ab -R2 ab of staphylococcal Atl interact with human thrombospondin 1 and vitronectin. Conclusion: The staphylococcal Atl repeats possess adhesive properties for human thrombospondin 1 and vitronectin. Significance: Repeats of Atl display multiple adhesive functions contributing to Staphylococcus-host interactions.

Pneumococcal Adhesins PavB and PspC Are Important for the Interplay with Human Thrombospondin-1

“…After bleeding, purification of IgG was performed using Protein A-Sepharose (Sigma) affinity chromatography. The polyclonal mouse anti-hTSP-1 IgG was generated as previously described (29). Polyclonal antibodies against pneumococci were generated by subcutaneous immunization of rabbits with a suspension of 1 ϫ 10 9 heat inactivated bacteria in 0.15 M sodium chloride.…”

“…Isolation and Purification of Human TSP-1-Human thrombospondin-1 was purified from human platelets as described recently (29).…”

“…Binding of hTSP-1 to the eukaryotic cell surface and ECM components is well characterized, whereas the interaction partners on the bacterial site are largely unknown. In a recent study we were able to identify repeating structures of the main staphylococcal autolysin Atl in S. aureus and Staphylococcus epidermidis as a direct binding partner for hTSP-1 (29). Furthermore, the extracellular adherence protein (Eap) of S. aureus was shown to bind hTSP-1 (30).…”

“…In addition to the mentioned functions in eukaryotic organisms, Gram-positive bacteria were shown to recruit soluble hTSP-1 to their surface in a dose-dependent manner. This binding increases bacterial adhesion and invasion into various epithelial and endothelial cells, as shown for S. pneumoniae, Staphylococcus aureus, and other Gram-positive human pathogens but not for Gram-negative bacteria (28,29). Binding of hTSP-1 to the eukaryotic cell surface and ECM components is well characterized, whereas the interaction partners on the bacterial site are largely unknown.…”

“…In previous experiments pneumococci showed a strong and dose-dependent acquisition of soluble hTSP-1 to their surface (29). Therefore, this study aimed to identify hTSP-1-binding proteins of S. pneumoniae.…”