vWbp mediates shear-dependent adhesion of S aureus to VWF. (A) Microparallel flow chamber perfusion over coated VWF (50 μg/mL) with fluorescently labeled wild-type (WT) and vwb strains at shear rates of 500 seconds⁻¹ and 1000 seconds⁻¹ in medium (n ≥ 6). (B) Perfusion over coated collagen with WT and vwb strains at 500 seconds⁻¹ or 1000 seconds⁻¹. VWF (60 μg/mL) was present in the medium where indicated (n ≥ 4). (C) Perfusion over coated collagen with WT or vwb strains in the presence of VWF-deficient plasma at 1000 seconds⁻¹. VWF (60 μg/mL) was added where indicated (n ≥ 4). All results are expressed as mean ± SEM. *P < .05, **P < .01, ***P < .001.