Early and late events in streptolysin-O induced hemolysis

Effect of Escherichia coli hemolysin on permeability of erythrocyte membranes to calcium

The extracellular hemolysin produced by porcine strains of E. coli effects a marked increase in the calcium permeability of erythrocyte membranes. This hemolysin promotes both calcium efflux from either calcium-loaded erythrocytes or erythrocyte ghosts and calcium accumulation during the pre-lytic period. Erythrocyte membrane calcium permeability was determined using either the radioisotope 45Ca or a calcium electrode. When similar concentrations of erythrocytes (35% packed cell volume) were treated with increasing amounts of hemolysin there was an increase in both the rate and the extent of calcium accumulation by the erythrocytes. These increases were due to increased numbers of erythrocytes becoming permeable to calcium as hemolysin concentrations increased, rather than increasing amounts of calcium being accumulated by individual erythrocytes. Hemolysins produced by porcine strains of E. coli from five geographical areas all increased calcium permeability of erythrocyte membranes.

Generation of leukotrienes from human granulocytes by alveolysin from Bacillus alvei

We investigated the effect of alveolysin on human granulocytes. Alveolysin is an exoprotein produced by Bacillus alvei and belongs to the group of sulfhydryl-activated cytolysins. Other members of this group are streptolysin O and theta-toxin from Clostridium perfringens. It is demonstrated that alveolysin leads to leukotriene generation from human granulocytes, which exert chemotactic (leukotriene B4) and slow-reacting substance (leukotriene C4, D4, and E4) activity under sublytic concentrations.