Killing of Leishmania Parasites in Activated Murine Macrophages is Based on an L‐Arginine‐Dependent Process That Produces Nitrogen Derivatives

摘要: The experiments described in this report were aimed at determining whether L-arginine (L-arg)-derived nitrogen oxidation products (nitric oxide, nitrous acid, nitrites) are involved the intracellular killing of Leishmania parasites by activated murine macrophages vitro. Peritoneal or bone marrow-derived infected with L. enriettii major, then exposure to recombinant interferon-gamma macrophage activating factor (MAF)-rich media presence lipopolysaccharide. Activation regular (i.e., arginine-containing) culture medium led complete destruction microorganisms within 24 h (L. enriettii) 48 major), concomitant accumulation nitrites (NO2-) fluids. When activation was carried out L-arg-free medium, however, neither parasite nor NO2- production obtained. A similar inhibition leishmanicidal activity and release observed using treated arginase (which converts L-arg urea ornithine), supplemented NG-monomethyl-L-arg guanidine inhibit conversion products). In all these situations, an excellent correlation between levels observed, whereas no strict detectable superoxide production. Intracellular parasitemore » could be prevented addition iron salts incubation Incubation free NaNO2 acid pH immobilisation, multiplication arrest, morphological degeneration microorganisms. Similarly, cells without affecting viability.« less