Nitric oxide is not involved in the killing of Trypanosoma cruzi by chicken macrophages

It is known that chicken macrophages derived in vitro from blood monocytes have the capacity to destroy Trypanosoma cruzi, but Toxoplasma gondii can s urvive within these cells. This study was performed to determine the involv ement of nitric oxide (NO) in the killing of T, cruzi by chicken macrophage s. Activated (by interferon-gamma and lipopolysaccharide) mouse peritoneal macrophages were used as controls. Macrophages were infected with T. cruzi and T. gondii; after 2, 24, and 48 h, NO was assayed using the Griess reage nt, Respiratory-burst involvement, revealed by the reduction of nitroblue t etrazolium (NBT), was determined in chicken macrophages. Chicken macrophage s did not produce NO: mouse macrophages were capable of producing NO with n o multiplication of parasites. Reduction of NET could be detected in chicke n macrophages that interacted with T. cruzi but was absent in those that in teracted with T. gondii. These results demonstrate that chicken macrophages do not use NO as a microbicidal agent when infected with T. cruzi or T. go ndii.