PROTECTIVE OPSONIC ACTIVITY OF ANTIBODIES AGAINST FIBRONECTIN-BINDINGPROTEINS (FNBPS) OF STAPHYLOCOCCUS-AUREUS

In this report, opsonic activity of hyperimmune rabbit IgG against fib ronectin-binding proteins (gal-FnBP A and ZZ-FnBP B) of Staphylococcus aureus is described. Moreover, the action of IgG purified from serum of rabbits immunized with 'combined vaccine' (fibronectin-binding prot ein A+collagen-binding protein+alpha-toxoid) is shown. The opsonic act ivity has been studied in an in vitro phagocytosis assay as well as in vivo. Mice which had been infected intraperitoneally with S. aureus s train Cowan 1 pretreated (opsonized in vitro) with specific anti-FnBPs IgG were able to eliminate the staphylococci from the peritoneal cavi ty and liver more rapidly than controls. Also, clearance from the bloo dstream of intravenously injected S. aureus Cowan 1 as well as S. aure us U320, opsonized with IgG anti-FnBPs or anti-FnBP+CnBP+alpha-toxoid, was more effective than observed in control groups. In other in vivo experiments it was shown that mice passively immunized with hyperimmun e IgG anti-FnBP (one or two doses, intravenously) before challenge wit h S. aureus Cowan 1 eliminated the bacteria better than controls injec ted only with preimmune IgG.