VWF binds to immobilized human vimentin. (A) Increasing concentrations of purified plasma VWF were mixed with ristocetin (0.2 mmol/L) (♦) or buffer (▪) and incubated with immobilized vimentin. Bound VWF was determined by ELISA using the polyclonal anti-VWF antibody. The VWF bound to vimentin in a ristocetin-dependent manner. Each point represents mean ± SD of 5 determinations, with a P < .01. (B) The binding of vimentin (96 nmol/L) to immobilized VWF was measured in the presence of the A2 domain at the indicated concentrations or the same volume of buffer in the control mixture. Bound vimentin was detected by using an HRP-conjugated anti-vimentin antibody. 100% is defined as the fraction of added vimentin bound in the absence of the A2 domain. Each point represents the mean ± SD of 4 determinations, P < .05 for each point.