Effects of phospholipase C on human erythrocytes.

Previous studies have shown that the bacterial exoenzyme phospholipase C permanently alters the chemical structure of erythrocyte ghosts. The present investigation has shown some of the functional, chemical and structural changes that sequentially occur when intact human red blood cells are lysed by this enzyme. Following exposure to the enzyme, membrane phospholipids were hydrolyzed with the removal of lipid phosphorus. This resulted in a shrinkage of cell size, sphering, and increased susceptibility to osmotic stress. Progressive hemolysis ensued, leaving ghosts which were characterized by focal electron-dense areas intimately associated with each membrane. These findings illustrate that the degradation of exposed phospholipids results in chemical and morphological damage to the cell membrane, which in turn alters its functional capabilities and results in lysis of the cell. Finally, these data support a newly proposed structural model of the cell membrane.