Effects of LPS on platelet adhesion to fibrinogen-coated plates. Isolated platelets (1 × 10⁶/mL) from wild-type mice or TLR4^def mice were untreated or treated with LPS (5 μg/mL) or thrombin (0.2 U/mL). Adhesion of platelets to fibrinogen-coated plates was analyzed by using a parallel-plate flow chamber (see “Materials and methods”). Data are expressed as the arithmetic mean ± SEM from 4 separate donors of platelets in each group, in which 4 to 6 fields were analyzed. ^*P < .05 versus untreated platelets from wild-type mice. #P < .01 versus thrombin-treated platelets from wild-type mice.