title: Leishmania mexicana: acid phosphatase ultrastructural cytochemistry of infected mouse macrophage cultures treated with phenazine methosulfate.
abstract: Bone marrow-derived mouse macrophage cultures infected with Leishmania mexicana amazonensis amastigotes were given a 2-hr pulse with 10 microM phenazine methosulfate (PMS), a cationic electron carrier which destroys the intracellular parasites. Cultures were fixed at different times after the PMS pulse and processed for the detection of acid phosphatase (AcP) activity at the electron microscopic level. Only a small proportion of nontreated, infected macrophages stained for AcP. In contrast, 2 to 6 hr after exposure to PMS, many infected cells displayed AcP-positive lysosomes and parasitophorous vacuoles. This increased AcP reactivity paralleled the reduction in the percentage of morphologically intact parasites. In addition, qualitative observations indicated that while nontreated infected cells contained only few recognizable lysosomes, the lysosomal complement noticeably increased a few hours after exposure to PMS. Most intact intracellular amastigotes were not stained, but damaged parasites were often positive for AcP. Twenty hours after the PMS pulse, the percentage of AcP-positive macrophages dropped to the levels initially present in noninfected cultures and all of the parasites were destroyed. Exposure of noninfected macrophages to PMS did not affect their AcP reactivity.
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D007891:Leishmania / Q000187:drug effects*; D008247:Lysosomes / Q000201:enzymology / Q000648:ultrastructure; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology / Q000469:parasitology*; D008773:Methylphenazonium Methosulfate / Q000494:pharmacology*; D051379:Mice; D008854:Microscopy, Electron; D010619:Phenazines / Q000494:pharmacology*; D014617:Vacuoles / Q000201:enzymology / Q000648:ultrastructure
chemical_list: D010619:Phenazines; D008773:Methylphenazonium Methosulfate; D000135:Acid Phosphatase