Calcium accumulation in human and sheep erythrocytes that is induced by Escherichia coli hemolysin.

The membrane permeability of both human and sheep erythrocytes is modified by an Escherichia coli-produced extracellular hemolysin. Alterations in membrane permeability were determined by measuring changes in the extracellular concentration of radiolabeled compounds that had been added to a 30-35% erythrocyte suspension. During the pre-lytic period, the E. coli hemolysin promotes calcium accumulation by both human and sheep erythrocytes. The concentration of calcium associated with the cells rises to a level that is approximately 1.5 (sheep) to 3 (human) times higher than that in a comparable volume of extracellular solution. Hemolysin also causes a rapid depletion of the high intracellular potassium levels normally present in human erythrocytes. That neither inulin, sucrose nor phosphate is accumulated by hemolysin-treated erythrocytes indicates that hemolysin makes the membrane selectively permeable to cations.