[Disappearance of specific membrane components during reticulocyte maturation in sheep]

Using antibodies prepared against whole reticulocyte suspensions, it is possible to identify specific membrane proteins from sheep reticulocytes. These membrane proteins can be isolated using the antibodies and Staphylococcus A protein to precipitate the immune complex. With fluorescein-labelled antireticulocyte antibody it may be shown that only reticulocytes and not red cells become fluorescent on exposure to the antibody, confirming that the antibody is directed against reticulocytes. Using either immobilized antibody columns or immobilized transferring columns, the same peptide bands from the membrane are retained by either column. The data suggest that the antibody is directed against the transferrin receptor. When the antibody is incubated for several hours with the reticulocytes, the cells release vesicles containing the transferrin receptor. This release is energy dependent since the process is inhibited by agents which interfere with metabolic activity.