LPS binding to platelets by TLR4 and CD62. (A) PRP incubated with mouse anti-human TLR4 (filled) or isotype control (open) showing binding of the TLR4 antibody to 51% of the platelet population. (B) Preincubation of washed thrombin-stimulated platelets with anti-CD62 at saturating (30 μg/mL, thin line) and subsaturating (10 μg/mL, bold line) concentrations reduced LPS binding by 95% and 47%, respectively, compared with platelets that were not preincubated (filled). (C) Preincubation of washed thrombin-stimulated platelets with anti-TLR4 at saturating (30 μg/mL, bold line) and subsaturating (7.5 μg/mL, thin line) concentrations reduced LPS binding by 92% and 52%, respectively, compared with platelets that were not preincubated (filled). (D) Preincubation with anti-TLR4 and anti-CD62, simultaneously, reduced LPS binding at saturating (thin) and subsaturating (bold) concentrations (98% and 96% reduction, respectively). In all experiments in which washed platelets were used (B-D), LPS was diluted in donor plasma.