TLR4 expression on platelets by flow cytometry. Platelets from wild-type (WT) and TLR4^def (TLR4^def) mice were isolated and stained for TLR4 expression (see “Materials and methods”). (A) Representative histogram obtained by flow cytometry for TLR4 stain. In each histogram, the percentage of positive cells for TLR4 is shown. (B) Mean fluorescence intensity obtained by flow cytometry. (C) TLR4 expression observed by using ¹²⁵I-anti-TLR4 mAb. Data are expressed as the arithmetic mean ± SEM from 3 to 6 separate donors of platelets in each group. ^*P < .01 relative to wild-type mice.