Protein A Is a Key Factor in Neutrophil Extracellular Traps Formation.

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 -induced NETosis. We determined the Protein A production of four different 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 strain in which Protein A as well as a second binding protein for immunoglobulins () have been knocked-out (Δ Δ) 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 did not induce NETosis. In conclusion, Protein A is a determinant for NETosis induction by .