Ex vivo and in vivo biological behavior of Leishmania (Viannia) shawi

São Paulo University Medical School Department of Pathology Av. Dr. Arnaldo, 455 01246-903 São Paulo SP Brazil
Parasitology Research (Impact Factor: 2.85). 11/2009; 105(6):1741-1747. DOI: 10.1007/s00436-009-1614-7
Source: PubMed

ABSTRACT Since the first description of Leishmania (Viannia) shawi, few studies were performed with this parasite. In the present work, the in vivo and ex vivo behavior of L. (Viannia) shawi infection was studied using murine model. Peritoneal macrophages from BALB/c and C57BL/6 mice were infected with promastigotes
in the stationary phase of growth; after 24h, the infection index and nitric oxide (NO) levels in the supernatant of the
cultures were analyzed. BALB/c and C57BL/6 mice were infected into the hind footpad, and at each 2weeks, mice were sacrificed,
and the histological changes of the skin inoculation site, parasitism, and humoral immune responses were evaluated during
8weeks. Ex vivo experiments showed that macrophages of BALB/c presented higher infection index and lesser NO levels than
macrophages of C57BL/6. In vivo experiments showed that BALB/c presented higher lesion size than C57BL/6 mice; similarly,
the histopathological changes and the parasitism in skin were more exacerbate in BALB/c mice. In draining lymph nodes, the
main change was increase of germinative centers, and parasites were detected from 6weeks pi onwards in both mice strain.
IgG was detected in BALB/c mice from 4weeks, while in C57BL/6, from 6weeks pi onwards. Taken together, these results indicate
that BALB/c showed a classical behavior of susceptibility when compared to C57BL/6 mice.

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