Changes in the cell membrane of erythrocytes in tumor-bearing rats

Cell electrophoresis of erythrocytes taken from AH 7974 hepatoma-bearing rats showed a marked decrease in the surface negative charge, as represented by a decrease in cell mobility. This change in the erythrocyte membrane began during the stationary phase of growth of transplanted tumor cells and became more pronounced in the late phase, during which time a marked decrease in the amount of sialidase-sensitive sialic acid present in the plasma membrane also took place. The erythrocytes of AH 7974F-bearing rats (which died from tumor growth much earlier than the AH 7974-bearing rats) had a similar, but less marked, decrease in their electrophoretic mobility and in the amount of sialidase-sensitive sialic acid present. These erythrocytes all had somewhat abnormal cell morphology, their shapes being slightly spherocytic.