The role of sialic acid in the determination of survival of rabbit erythrocytes in the circulation

Evidence is presented to indicate a generalized role for the terminal sialic acid residues of circulating erythrocytes of rabbit. Neuraminidase is shown to remove only sialic acid from these erythrocytes. Neuraminidase-treated and intact rabbit erythrocytes have similar in vitro properties, except those of cellular charge and cellular adhesion in their sera. These properties include similar shape, osmotic fragility curve, autohemolysis at 37°, K⁺ retention and pyruvate kinase activity. The D-glucose 6-phosphate dehydrogenase and the cholinesterase activities are higher on the neuraminidase-treated erythrocytes than on the intact ones. After injection into rabbits, the sialic acid-less erythrocytes tested, were promptly removed from the circulation; intact erythrocytes, previously incubated under the same conditions but without neuraminidase, were removed from the circulation after a significantly longer period.