@article{mbs:/content/journal/micro/10.1099/mic.0.000293, author = "Kuipers, Annemarie and Stapels, Daphne A. C. and Weerwind, Lleroy T. and Ko, Ya-Ping and Ruyken, Maartje and Lee, Jean C. and van Kessel, Kok P. M. and Rooijakkers, Suzan H. M.", title = "The Staphylococcus aureus polysaccharide capsule and Efb-dependent fibrinogen shield act in concert to protect against phagocytosis", journal= "Microbiology", year = "2016", volume = "162", number = "7", pages = "1185-1194", doi = "https://doi.org/10.1099/mic.0.000293", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000293", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "staphylococci", keywords = "capsule", keywords = "fibrinogen", keywords = "phagocytosis", abstract = " Staphylococcus aureus has developed many mechanisms to escape from human immune responses. To resist phagocytic clearance, S. aureus expresses a polysaccharide capsule, which effectively masks the bacterial surface and surface-associated proteins, such as opsonins, from recognition by phagocytic cells. Additionally, secretion of the extracellular fibrinogen binding protein (Efb) potently blocks phagocytic uptake of the pathogen. Efb creates a fibrinogen shield surrounding the bacteria by simultaneously binding complement C3b and fibrinogen at the bacterial surface. By means of neutrophil phagocytosis assays with fluorescently labelled encapsulated serotype 5 (CP5) and serotype 8 (CP8) strains we compare the immune-modulating function of these shielding mechanisms. The data indicate that, in highly encapsulated S. aureus strains, the polysaccharide capsule is able to prevent phagocytic uptake at plasma concentrations <10 %, but loses its protective ability at higher concentrations of plasma. Interestingly, Efb shows a strong inhibitory effect on both capsule-negative and encapsulated strains at all tested plasma concentrations. Furthermore, the results suggest that both shielding mechanisms can exist simultaneously and collaborate to provide optimal protection against phagocytosis at a broad range of plasma concentrations. As opsonizing antibodies will be shielded from recognition by either mechanism, incorporating both capsular polysaccharides and Efb in future vaccines could be of great importance.", }