- Saotomo Itoh (Department of Molecular and Cellular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University / firstname.lastname@example.org)
1) Department of Molecular and Cellular Health Sciences, Graduate School of Pharmaceutical Sciences, Nagoya City University , 2) Department of Microbiology, Hoshi University School of Pharmacy and Pharmaceutical Sciences
Staphylococcal superantigen-like 10 (SSL10) is one of the immunoglobulin G (IgG) binding proteins produced by Staphylococcus aureus (S. aureus). SSL10 is reported to bind to Fc region of human IgG and interfere its effector functions. As SSL10 shows no homology with other staphylococcal IgG binding proteins, the mechanism of interaction between SSL10 and IgG remains to clear. In this study we attempted to identify the regions of SSL10 that are responsible for binding to human IgG (hIgG) by analyzing the binding ability of chimeras between SSL10 and its paralog, SSL7. The chimeras that retained either β1-β3 or β10-β12 of SSL10 bound to immobilized hIgG. On the other hand, chimeras that lacked both of these regions did not show binding activity to hIgG. In far western analysis, biotinylated hIgG interacted with SSL10 and chimera that retained β1-β3 and β10-β12 of SSL10. Collectively, SSL10 has two responsible regions for binding to hIgG, one is located in N-terminal half of oligonucleotide/oligosaccharide-binding (OB)-fold domain and the other is in C-terminal half of β-grasp domain. These findings would contribute to understand the mechanism of immune evasion of S. aureus and also to develop vaccines and drugs against S. aureus.