Influence of red cell shape on surface charge topography

Human red blood cells (RBCs), transformed from discocytes into crenated shapes by incubation in hyperosmotic NaCl, have increased rates of agglutination in the presence of either poly-l-lysine (PLL) or soybean agglutinin (SBA). Reversion to discocytes by resuspension in isoosmotic NaCl lowers agglutination rates back to normal levels. Crenation also causes a reversible decrease in the binding of cationized ferritin (CF) particles/μm² of RBC surface area and focal clustering of CF particles. The decrease in CF binding and focal CF clustering are probably due to a rearrangement of negative charge bearing molecules such as glycoproteins on the RBC surface. Clustering of membrane glycoproteins may also account for the increased agglutination rates with PLL and SBA. These observations support the hypothesis that integral membrane proteins which bear negative charges and receptors at the RBC surface are associated with a cytoskeleton within the red cell. Distortion of the RBC cytoskeleton may induce a redistribution of integral membrane proteins and thus modify the surface properties of the cell.