Role of Sialic Acid in Survival of Erythrocytes in the Circulation: Interaction of Neuraminidase-Treated and Untreated Erythrocytes with Spleen and Liver at the Cellular Level

Sialidase (neuraminidase; acylneuraminyl hydrolase; EC 3.2.1.18)-treated erythrocytes obtained from different species are susceptible to rapid elimination from the circulation and are sequestered in the liver and spleen. The present studies were concerned with the mechanism of this clearance and how it may relate to the normal physiological process of removing senescent erythrocytes from the circulation. The results obtained indicate a preferential recognition of sialidase-treated as compared to normal erythrocytes by mononuclear spleen cells and Kupffer cells of the liver. This recognition manifests itself in both autologous and homologous systems by adhesion of the complementary cells in the form of rosettes, and as such could explain the removal of enzyme-treated erythrocytes from the circulation with their accumulation in liver and spleen. This phenomenon may represent a normal physiological mechanism for removal of senescent erythrocytes containing decreased sialic acid.