Effect of deoxygenation on the accessibility of ankyrin epitopes in transgenic murine erythrocytes evaluated by both immunofluorescence staining and flow cytometry. (A) RBCs were oxygenated or deoxygenated, then fixed and stained with a monoclonal antibody to ankyrin. The stained RBCs were observed using a confocal fluorescence microscope (top) and further analyzed for antiankyrin fluorescence staining intensity by flow cytometry (bottom). (B) Mean fluorescence intensity (MFI) of antiankyrin staining in oxygenated and deoxygenated erythrocytes. The relative MFI of oxygenated erythrocytes was set at 1 and compared with the MFI of the deoxygenated RBCs (mean of 3 experiments ± SD).