Clearance of senescent erythrocytes: wheat germ agglutinin distribution on young and old human erythrocytes.

To add an additional aspect to the process of recognition and removal of senescent human erythrocytes from the circulation, the binding of wheat germ agglutinin (WGA) to separated young, old and sialidase-treated human erythrocytes is evaluated with the immune-electron microscopical method. WGA/gold conjugate binding to old erythrocytes was lower (27%) than to young erythrocytes and even lower following treatment with sialidase (82%), exhibiting a clustered, non-continuous labeling pattern in all three erythrocyte populations, thus showing a possible redistribution of WGA binding sites. The decrease in bound WGA/gold particles correlates well with the previously reported decrease in surface sialic acid on old erythrocytes. The binding of WGA/gold are indicative of the changes occurring on erythrocyte membrane surfaces when interacting with different agglutinins.