VITRONECTIN-BINDING STAPHYLOCOCCI ENHANCE SURFACE-ASSOCIATED COMPLEMENT ACTIVATION

Coagulase-negative staphylococci are well recognized in medical device -associated infections, Complement activation is known to occur at the biomaterial surface, resulting in unspecific inflammation around the biomaterial, The human serum protein vitronectin (Vn), a potent inhibi tor of complement activation by formation of an inactive terminal comp lement complex, adsorbs to biomaterial surfaces in contact with blood, In this report, we discuss the possibility that surface-immobilized V n inhibits complement activation and the effect of Vn-binding staphylo cocci on complement activation on surfaces precoated with Vn, The exte nt of complement activation was measured with a rabbit anti-human C3c antibody and a mouse anti-human C9 antibody, raised against the neoepi tope of C9, Our data show that Vn immobilized on a biomaterial surface retains its ability to inhibit complement activation, The additive co mplement activation-inhibitory effect of Vn on a heparinized surface i s very small, In the presence of Vn-binding strain, Staphylococcus hem olyticus SM131, complement activation on a surface precoated with Vn o ccurred as it did in the absence of Vn precoating, For S. epidermidis 3380, which does not express binding of Vn, complement activation on a Vn-precoated surface was significantly decreased, The results could b e repeated on heparinized surfaces. These data suggest that Vn adsorbe d to a biomaterial surface may serve to protect against surface-associ ated complement activation, Furthermore, Vn-binding staphylococcal cel ls may enhance surface-associated complement activation by blocking th e inhibitory effect of preadsorbed Vn.