Effects of MCD treatment on in vitro vesicle expulsion from erythrocytes from

SR-BI^−/−/apoE^−/−mice. Erythrocytes fromSR-BI^−/−/apoE^−/−mice were preincubated for 5 minutes in medium with (this Figure) or without (not shown; however, see Figure 6) 0.1% MCD; cells were then incubated in vitro without MCD as described in Figure 6. Samples were taken before MCD treatment (panel A) and at 24 (panel B) and 48 (panel C) hours of incubation and analyzed by electron microscopy. At 24 hours (panel B) and 48 hours (panel C), the membrane-enclosed, cytoplasmic vesicles appear to be undergoing expulsion from theSR-BI^−/−/apoE^−/−erythrocytes (red arrows). The plots below each electron micrograph correspond to the photos above and show a decrease in filipin staining as plotted against FSC. The rectangles on the 24- and 48-hour plots show the position of the bulk population of cells at 0 hours. Preincubation without MCD (data not shown) gave results similar to those shown in Figure 6.