On the mechanism of killing of Trypanosoma cruzi by human polymorphonuclear leukocytes.

The temperature-dependence of some processes involved in the killing of sensitized T. cruzi epimastigotes by human polymorphonuclear leukocytes (PMN) was determined. The rate of the reactions was related to the temperature of incubation according to the Arrhenius equation and the apparent energies of activation (Ea) were calculated. The Ea values separated these complex reactions into two groups: one with Ea of about 10 kcal/mol for the phagocytosis of the parasites and the release of lysosomal enzymes by PMN, and the other with Ea of about 22 kcal/mol for the cytotoxicity against sensitized T. cruzi, the rate of oxygen consumption by PMN, and the lysis of the parasites with added hydrogen peroxide.