Blocking A1-domain of VWF inhibits S aureus binding to collagen under shear stress. (A) Perfusion over coated collagen with fluorescently labeled WT strain and 60 μg/mL VWF in medium at a shear rate of 1000 seconds⁻¹. Anti-A1 VWF domain antibody (Ab) 6D1 (final concentration 10 μg/mL) or anti-tPa monoclonal immunoglobulin G1 Ab (10 μg/mL) were added where indicated (n ≥ 5). (B) Perfusion over coated collagen at 1000 seconds⁻¹ with WT strain in PPP and PRP (PPP or PRP preincubation of 15 minutes at 37°C). 6D1 (final concentration 10 μg/mL) was added where indicated (n ≥ 4). All results are expressed as mean ± SEM. *P < .05, **P < .01.