AUTHOR=Hoppenbrouwers Tamara , Sultan Andi R. , Abraham Tsion E. , Lemmens-den Toom Nicole A. , Hansenová Maňásková Silvie , van Cappellen Wiggert A. , Houtsmuller Adriaan B. , van Wamel Willem J. B. , de Maat Moniek P. M. , van Neck Johan W. TITLE=Staphylococcal Protein A Is a Key Factor in Neutrophil Extracellular Traps Formation JOURNAL=Frontiers in Immunology VOLUME=Volume 9 - 2018 YEAR=2018 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.00165 DOI=10.3389/fimmu.2018.00165 ISSN=1664-3224 ABSTRACT=Staphylococcus aureus (S. aureus) are strong inducers of Neutrophil Extracellular Traps (NETs), a defense mechanism of neutrophils against pathogens. Our aim was to explore the role of Protein A in S. aureus-induced NETosis. We determined the Protein A production of four different S. aureus strains and found a direct relationship between the degree of NETosis induction and Protein A production: strains producing higher concentrations of Protein A evoke significantly more NETs. A S. aureus strain in which Protein A as well as a second binding protein for immunoglobulins (Sbi) have been knocked-out (ΔSpA ΔSbi) induced significantly less NETosis than the wild type strain. NETosis induction by this knockout strain can be rescued by the addition of purified Protein A. Dead S. aureus did not induce NETosis. In conclusion, Protein A is a determinant for NETosis induction by S. aureus.