Papel de linfócitos Th17 durante a infecção experimental por Leishmania infantum/chagasi / Role of Th17 lymphocytes during Leishmania infantum/chagasi infection

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

16/02/2012

RESUMO

Visceral leishmaniasis (LV) is a chronic and potentially fatal disease caused by Leishmania donovani and Leishmania infantum/chagasi. The development of Th1 response is classically associated with protection against these parasites, but recent data also show that there is a positive correlation between the Th17-related cytokines production and the protection against LV by L. donovani in humans. However, the role of this CD4+ T cells subset during L. infantum/chagasi infection remains unknown. In this study, our aim was to evaluate the Th17 and related cytokines participation, besides the mechanism by which these cells playing during the L. infantum/chagasi infection.The results showed that the parasite induces high amounts of TGF-, IL-1, IL-6, and IL-23 by bone marrow-derived dendritic cells (BMDC), cytokines involved with Th17 induction and/or maintenance. Accordingly, naïve-C57BL/6 spleenocytes co-cultured with L. infantum/chagasi-infected BMDC produced significant amounts of IL-17 by TCD4+. Interestingly, IL-17 was produced in high amounts in the liver and spleen of WT infected-mice, being peaked at 4th and 6th weeks after infection. The Th17 is critical for protective immunity against L. infantum/chagasi, since that IL-17R-/-, IL-23p19-/- and IL-6-/- infected-mice showed increasing of parasite load associated with enhancement of IL-10 production in IL-17R-/- compared to WT infected-mice. Strictly, in the absence of IL-17 signaling, a smaller inflammatory infiltrate was observed in the liver. Interestingly, IL-17 production was potentiated in IL-10-/- infected-mice, and they were more resistant to infection, showing reduced parasites numbers in the spleen and liver. In addition to promoting protection through the downmodulation of IL-10, IL-17 enhanced the NO production. Together, our results demonstrate that L. infantum/chagasi trigger Th17 response that promotes the host protection during infection.

ASSUNTO(S)

leishmania infantum/chagasi leishmania infantum/chagasi leishmaniose visceral linfócitos th17 th17 response visceral leishmaniasis

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