Fate of biotinylated erythrocytes from

SR-BI^−/−/apoE^−/− mice transfused into wild-type andSR-BI^−/−/apoE^−/−recipients. A donorSR-BI^−/−/apoE^−/−mouse was injected with biotin to label erythrocytes in vivo. Samples of this blood were then injected into either wild-type (panels A-C) orSR-BI^−/−/apoE^−/−(panels D-F) recipient mice. Samples of blood from these recipient mice were taken immediately after infusion (panels A,D), at 24 hours (panels B,E), and at 48 hours (panels C,F), and the cells were labeled with Lysotracker. Blood cells were analyzed by confocal microscopy showing biotin in red and Lysotracker in green. Immediately following transfusion, 9.4% of the cells in the wild-type recipient were labeled with biotin. This decreased to 9.1% at 24 hours and to 6.0% at 48 hours, for a 48-hour survival rate of 64%.