Activation of the calcium permeability of erythrocyte membranes by perfringolysin O.

Calcium ions inhibited perfringolysin O-induced hemolysis at a concentration lower than 1 mM, but not the hemolysis by digitonin at 10 mM. The introduction of calcium ions into ghosts inhibited the lysis more strongly than the addition of calcium ions outside ghosts. When erythrocytes were treated with perfringolysin O in the presence of 1 mM CaCl2 containing 45CaCl2, the radioactivities inside cells rapidly increased during incubation. On the other hand, when perfringolysin O-treated erythrocytes were incubated in a calcium-free medium, the erythrocytes released calcium ions at a 3.3-fold higher rate than untreated cells. These results suggested that perfringolysin O accelerated both the calcium influx into and efflux from erythrocytes.