Human erythrocytes shed exocytic vesicles in vivo.
Studies were designed to demonstrate whether red cells (RBCs) lose membrane segments in vivo. Plasma separated from fresh blood collected in citrate-phosphate-dextrose-adenine-one was passed through 0.8 mu nitrocellulose filters to remove residual RBCs and formed elements. Exocytic vesicles were separated by centrifugation at 70,000 X g. Transmission electron microscopy showed vesicles 50 to 200 nm in diameter which contained hemoglobin. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of vesicle membranes showed that spectrin bands 1 and 2 and ankyrin band 2.1 were absent. These observations are the initial demonstration that RBCs shed exocytic vesicles in the normal circulation.
D004910:Erythrocyte Membrane / Q000502:physiology; D004912:Erythrocytes / Q000502:physiology*; D005089:Exocytosis; D006801:Humans; D008565:Membrane Proteins / Q000097:blood
D008565:Membrane Proteins