Department of Biomedical and Diagnostic Sciences, University of Tennessee, Knoxville, Tennessee, United States of America.
Department of Microbiology, Faculty of Veterinary Medicine, Zagazig University, Zagazig, Egypt.
PLoS One. 2019 Jul 23;14(7):e0219817. doi: 10.1371/journal.pone.0219817. eCollection 2019.
The success of staphylococci as pathogens has been attributed, in part, to their ability to evade their hosts' immune systems. Although the proteins involved in evasion have been extensively studied in staphylococci affecting humans little characterization has been done with Staphylococcus pseudintermedius, an important cause of pyoderma in dogs. Staphylococcus aureus binder of immunoglobulin (Sbi) interferes with innate immune recognition by interacting with multiple host proteins. In this study, a S. pseudintermedius gene that shares 38% similarity to S. aureus Sbi was cloned from S. pseudintermedius strains representative of major clonal lineages bearing two paralogs of the protein. Binding of immunoglobulins and Fab and Fc fragments as well as interaction with complement was measured. S. pseudintermedius Sbi protein bound IgG from multiple species and canine complement C3, neutralized complement activity and bound to canine IgM and B cells. Evidence from this work suggests Sbi may play an important role in S. pseudintermedius immune evasion.
葡萄球菌作为病原体的成功部分归因于它们逃避宿主免疫系统的能力。尽管在影响人类的葡萄球菌中，逃避相关的蛋白已经得到了广泛的研究，但对化脓性链球菌（一种导致犬脓皮病的重要病原体）的研究却很少。金黄色葡萄球菌免疫球蛋白结合蛋白（Sbi）通过与多种宿主蛋白相互作用来干扰先天免疫识别。在这项研究中，从具有该蛋白两个同源物的主要克隆谱系的代表性中间葡萄球菌菌株中克隆了一个与金黄色葡萄球菌 Sbi 具有 38%相似性的中间葡萄球菌基因。测定了免疫球蛋白和 Fab 和 Fc 片段的结合以及与补体的相互作用。中间葡萄球菌 Sbi 蛋白结合了来自多种物种的 IgG 和犬补体 C3，中和了补体活性并结合了犬 IgM 和 B 细胞。这项工作的证据表明，Sbi 可能在中间葡萄球菌的免疫逃避中发挥重要作用。
