STAPHYLOCOCCUS-AUREUS FIBRONECTIN-BINDING PROTEINS (FNBPS) - IDENTIFICATION OF ANTIGENIC EPITOPES USING POLYCLONAL ANTIBODIES

Polyclonal antibodies against recombinant fibronectin-binding proteins (gal-FnBP A and ZZ-FnBP B) of Staphylococcus aureus were analyzed by both solid-phase and solution-phase methods. These antibodies were fou nd to bind homologous antigen and to cross-react with heterologous ant igen. It was also found that antibodies recognize native FnBP on the c ell surface. It has been shown, by the inhibition assay, that the majo rity of antibodies recognize a fibronectin-binding D1-D2 sequence of F nBP A. Anti-FnBP A Fab fails to bind the D3 sequence, though this pept ide used in a solution inhibits binding of fibronectin to immobilized FnBP A, similarly to D1 and D2 peptides. Since the anti-FnBP A antibod ies are able to block fibronectin binding to staphylococci by about 50 %, it is reasonable to assume that the bacterial receptor has addition al binding sites outside the D domain.