Secretion by Trypanosoma cruzi of a hemolysin active at low pH

Trypanosoma cruzi releases into the culture medium heat-labile, trypsin-sensitive molecules which lyse erythrocytes from various animal species. Production of the hemolysin is abolished by removal of glucose from the medium or by addition of the metabolic inhibitors sodium azide, 2-deoxy-D-glucose or puromycin. Sieving experiments with erythrocyte ghosts indicate that large channels are formed on the target membranes. The activity of the hemolysin is maximal at pH 5.5 and undetectable at neutral pH, indicating that it functions in acidic intracellular compartments. This agent could be involved in promoting the escape of T. cruzi into the cytoplasm of the host cell, by mediating the lysis of the membrane of the phagosome in which the parasite resides at early times after invasion.