Raft microdomains are essential for A-SMase outer leaflet localization. Daudi cells were preincubated (○) or not (□) with methyl-β-cyclodextrin during 20 minutes at 37°C for raft disruption and then treated or not with 10 μg/mL rituximab. For cholesterol depletion-repletion experiment (•), cells were first treated with methyl-β-cyclodextrin and then incubated with cholesterol as described in “Materials and Methods.” A-SMase localization was determined by FACS cytometry on nonpermeabilized cells. Results are the mean of 3 independent experiments ± SD.