Erythrocyte vesiculation: a self‐protective mechanism?

• Published in: British journal of haematology Vol. 141; no. 4; pp. 549 - 556
• Main Authors: Willekens, Frans L. A., Werre, Jan M., Groenen‐Döpp, Yvonne A. M., Roerdinkholder‐Stoelwinder, Bregt, De Pauw, Ben, Bosman, Giel J. C. G. M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-05-2008; Blackwell
• Subjects: Anion Exchange Protein 1, Erythrocyte - metabolism; band 3; Biological and medical sciences; CD55 Antigens - blood; CD59 Antigens - blood; Cell Fractionation - methods; erythrocyte ageing; Erythrocyte Aging - physiology; Erythrocyte Membrane - physiology; erythrocyte microparticles; Glycophorin - metabolism; Hematologic and hematopoietic diseases; Humans; Immunoglobulin G - blood; Medical sciences; phosphatidylserine exposure; Phosphatidylserines - blood; senescent cell antigen; Band 3 protein; Hematology; Ageing; Red blood cell; Exposure; erythrocyte ageing; band 3; Mechanism; Antigen; Prevention; senescent cell antigen; Blood cell; erythrocyte microparticles; Microparticle; Phosphatidylserine; phosphatidylserine exposure
• ISSN: 0007-1048; 1365-2141
• DOI: 10.1111/j.1365-2141.2008.07055.x

Summary
Previous studies demonstrated that 20% of haemoglobin is lost from circulating erythrocytes during their total lifespan by vesiculation. To study whether removal molecules other than membrane‐bound haemoglobin were present in erythrocyte‐derived vesicles, flow cytometry and immunoblot analysis were employed to examine the presence of phosphatidylserine (PS) and IgG, and senescent cell antigens respectively. It was demonstrated that 67% of glycophorin A‐positive vesicles exposed PS, and that half of these vesicles also contained IgG. Immunoblot analysis revealed the presence of a breakdown product of band 3 that reacted with antibodies directed against senescent erythrocyte antigen‐associated band 3 sequences. In contrast, only the oldest erythrocytes contained senescent cell antigens and IgG, and only 0·1% of erythrocytes, of all ages, exposed PS. It was concluded that vesiculation constitutes a mechanism for the removal of erythrocyte membrane patches containing removal molecules, thereby postponing the untimely elimination of otherwise healthy erythrocytes. Consequently, these same removal molecules mediate the rapid removal of erythrocyte‐derived vesicles from the circulation.