Figure 1: Dot plots for phosphatidylserine externalization of the apoptotic cells. We treated PMNLs (1.5 × 106/mL) for 2.5 h at 37°C without (a) or with (b) 25 μg/mL sulfatide (St) and stained them with Annexin V-Alexa Fluor 488 and PI and processed them by flow cytometer as described in Section 2. The percentage of viable cells (region O3), early apoptotic cells (region O4), and late apoptotic and necrotic cells (regions O2 and O1) is indicated. Representative dot plots are shown from four independent experiments.