Nitric oxide is involved in control of Trypanosoma cruzi-induced parasitemia and directly kills the parasite in vitro. Infect. Immun

This study was carried out to determine the role of reactive nitrogen intermediates in Trypanosoma cruzi infection. In vitro, splenocytes obtained during the acute phase of infection produced elevated amounts of nitric oxide (NO) that were correlated with the resistance or susceptibility of the animals. In vivo, the levels of N02 plus N03 in plasma during the later phase of infection were higher in C57BV6 mice than in BALBLJc mice. The treatment of infected C57BL/6 mice with inhibitors of NO synthase increased parasitemia and mortality. Finally, we found that the NO donor drug S-nitroso-acetyl-penicillamine is able to kill trypomastigotes in vitro in the absence of any other cells, suggesting a direct NO-mediated killing of T. cruzi. Trypanosoma cruzi, the causative agent of Chagas ' disease, is a hemoflagellate protozoan parasite that infects humans and a wide variety of mammals. Although the infected host develops specific cellular and antibody-mediated immune responses, the chronic infection is maintained by a few trypomastigotes in the blood and gives rise to a major public health problem, namely, the transmission of Chagas ' disease through blood transfusions (36)