Acridine orange induces translocation of phosphatidylserine to red blood cell surface

1 Department of Biochemistry, Hebrew University-Hadassah Medical School; 2 Blood Bank, Hadassah University Hospital; and 3 Department of Hematology, Hadassah University Hospital, Jerusalem, Israel 91120 Submitted 22 November 2002 ; accepted in final form 1 May 2003 Clustering of band-3 on red blood cell (RBC) surface has been assumed to catalyze RBC phagocytosis. In studying this subject, acridine orange (AO) has commonly been employed on the assumption that it specifically induces band-3 clustering. In the present study, we show that AO strongly induces translocation of phosphatidylserine (PS) to RBC surface. Because surface PS is well known to induce RBC intercellular interaction, these findings suggest that the use of AO as a specific inducer of band-3 clustering is questionable. It is possible that band-3 clustering and PS translocation are interdependent, and this interrelationship has yet to be explored. erythrocytes; adherence; acridine orange; band-3; phosphatidylserine Address for reprint requests and other correspondence: S. Yedgar, Dept. of Biochemistry, Hebrew Univ.-Hadassah Medical School, Jerusalem, Israel 91120 (E-mail: yedgar{at}md2.huji.ac.il ).