Effects of Staphylococcus aureus protein A on the production of primary host defense factors against S. aureus infection

Abstract

In vitro examination was carried out to investigate the effects of protein A of Staphylococcus aureus (S. aureus) on the production of fibronectin (Fn) and the third component of complement (C3) by macrophages and that of CD11b, CD49e and H2O2 by granulocytes. Fn production of cultured murine peritoneal macrophages (M phi ) increased significantly (P < 0.01) by treatment for 4 hr at 37 degrees C with recombinant PA (rPA) and the supernatant of overnight culture of S. aureus Cowan I strain (CoCS) (p < 0.01), not that of Wood 46 strain (WoCS), in comparison with that of control. The activity of rPA was inhibited strongly in the presence of CYH (1.0 microgram/ml). The production of C3 by cultured M phi did not increased by treatment for 4 hr at 37 degrees C with rPA, CoCS and WoCS. In these cells treated with CoCS and WoCS, however, the production increased by cultivation in serum free medium for a further 20 hr at 37 degrees C after the treatment. But increase was not found in rPA treated cells. On the other hand, the production of Mac-1, VLA-5 and H2O2 by granulocytes did not increase by treatment with rPA and CoCS. These results show that rPA and PA in CoCS are major components which stimulates Fn synthesis and secretion by cultured M phi some component(s) contained in the supernatant of overnight culture of S. aureus increased the production C3 by cultured M phi , and the supernatant may not contain stimulators to induce production of CD49e, CD11b and H2O2. Increase of Fn production of M phi by PA stimulation may play an important role in the primary host defense against S. aureus infection.