Clostridium perfringens alpha-toxin-induced hemolysis of horse erythrocytes is dependent on Ca 2+ uptake

Abstract

Clostridium perfringens alpha-toxin is able to lyse various erythrocytes. Exposure of horse erythrocytes to alpha-toxin simultaneously induced hot–cold hemolysis and stimulated production of diacylglycerol and phosphorylcholine. When A23187-treated erythrocytes were treated with the toxin, these events were dependent on the concentration of extracellular Ca 2+. Incubation with the toxin of BAPTA-AM-treated horse erythrocytes caused no hemolysis or production of phosphorylcholine, but that of the BAPTA-treated erythrocytes did. When Quin 2-AM-treated erythrocytes were incubated with the toxin in the presence of 45Ca 2+, the cells accumulated 45Ca 2+ in a dose- and a time-dependent manner. These results suggest that the toxin-induced hemolysis and hydrolysis of phosphatidylcholine are closely related to the presence of Ca 2+ in the cells. Flunarizine, a T-type Ca 2+ channel blocker, and tetrandrine, an L- and T-type Ca 2+ channel blocker, inhibited the toxin-induced hemolysis and Ca 2+ uptake. However, L-type Ca 2+ channel blockers, nifedipine, verpamil and diltiazem, an N-type blocker, ω-conotoxin SVIB, P-type blockers, ω-agatoxin TK and ω-agatoxin IVA, and a Q-type blocker, ω-conotoxin MVII C, had no such inhibitory effect. The observation suggests that Ca 2+ taken up through T-type Ca 2+ channels activated by the toxin plays an important role in hemolysis induced by the toxin.