02452nas a2200313   4500000000100000008004100001260001300042653001200055653002600067653002400093653001100117653001400128653001000142653000900152653002900161653003100190653001500221653003700236653001100273100002100284700002000305700001900325245007500344856004100419300001200460490000700472520164500479022001402124       2002                            d  c2002 Sep10aAnimals10aAntibodies, Bacterial10aAntigens, Bacterial10aFemale10aGranuloma10aLiver10aMice10aMycobacterium Infections10aMycobacterium lepraemurium10aPeroxidase10aSpecific Pathogen-Free Organisms10aSpleen1 aRojas-Espinosa O1 aWek-Rodriguez K1 aArce-Paredes P00aThe effect of exogenous peroxidase on the evolution of murine leprosy.  uhttp://ila.ilsl.br/pdfs/v70n3a04.pdf  a191-2000 v703 a<p>Mycobacterium lepraemurium (MLM) is a successful parasite of murine macrophages; in vitro, this microorganism infects macrophages without triggering these cells' ability to produce either the reactive oxygen intermediaries (ROI) or the reactive nitrogen intermediaries (RNI), and ends up lodging within these cells, that, in addition, do not contain myeloperoxidase (MPO). In this study, we analyzed the effect of exogenous peroxidase on the evolution of murine leprosy. Bacilli were intraperitoneally injected, either alone (MLM) or precoated with horseradish peroxidase (MLM-PO), into two different groups of mice. At two-week intervals, the groups were blood-sampled to measure the levels of antibodies to protein- or lipid-MLM antigens. The extent of the disease was also assessed by looking at the histopathologic changes that occurred both in the liver and the spleen of the infected animals. We found that the animals injected with MLM-PO developed a disease that evolved at a slower pace than the disease that occurred in the animals injected with intact MLM. The difference between groups, both in terms of antibody levels and histological changes, was clearly evident at the intermediate stages of the disease (2 to 2.5 months), but was not so obvious at the more advanced stage of 3 months. Several possibilities to explain how the PO-coated bacilli might have regained their infectiousness are discussed. Lowering the infective dose of MLM and MLM-PO from 5 x 10(7) bacilli to 5 x 10(6) bacilli would, probably, have resulted in a different outcome of the disease: more extended in the MLM-group than in the MLM-PO group.</p>  a0148-916X