Figure 7

Cross-link formation induced by vWbp-activated FXIII reinforces binding between FnBPA and Fbg-coated surface. Mixtures of vWbp, ProT and FnBPA N1N2N3 (A) or FnBPA N2N3 (B) were incubated with immobilized Fbg in the presence/absence of FXIII. Wells were extensively washed with increasing concentrations of NaCl. Binding of FnBPA proteins to Fbg was detected by addition of a mouse FnBPA antibody followed by secondary HRP-conjugated IgG to the wells. (C) The effect of increasing concentrations of NaCl on the adhesion of S. aureus LAC wt cells (red) or fnbAfnbB double mutant cells overexpressing FnBPB (green) or FnBPA (blue) to Fbg was evaluated by incubating Fbg-coated microtiter wells with a mixture of vWbp, ProT and bacterial cells in the presence of FXIII. Wells were then washed with the indicated concentrations of NaCl and the attached bacterial cells detected with crystal-violet. The effect of salt concentrations on S. aureus LAC adhesion in absence of FXIII is also shown (black). Adhesion levels are expressed as a percentage of controls, where washings of the wells were performed with 150 mM NaCl. Data are expressed as means ± S.D. of triplicate tests.