Avaliação do Efeito do Lipofosfoglicano (LPG) de Leishmania amazonensis e de Leishmania braziliensis na infecção por Leishmania / Avaliação do Efeito do Lipofosfoglicano (LPG) de Leishmania amazonensis e de Leishmania braziliensis na infecção por Leishmania

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

06/06/2008

RESUMO

The search for new drugs for the treatment of Leishmaniasis has focused in the understanding of the mechanisms in host-parasite interaction. This disease manifests itself in a wide array of manifestations due to both parasite- and host-related peculiarities. The early immune response caused by the parasite can be crucial in the development of infection and in the healing and/or resistance process. The Lipophospohglycan (LPG) molecule, present in large amounts in the surface of promastigotes forms, has shown great structural variability amongst the several species that belong to the Leishmania genus. Therefore, understanding the initial mechanisms of the interaction of LPG in the host- parasite relationship is an important step towards understanding the differences between the several presentations of this disease. In this work differences were verified in the proportion of the molecule of LPG in L. braziliensis and L. amazonensis evidencing the diversity structural and/or quantitative of this surface glycoconjugate. Despite the variability between LPGs, their inoculation in association with L. braziliensis in infections in mice were not capable to alter the lesion development provoked by the protozoan. However spleen and lymph node cells of mice infected with L. braziliensis and LPG were capable to produce the cytokine IL-10 which has an important role in the regulation of the immune response. Besides, purified LPGs were not capable to activate intraperitoneal macrophages. However, when added together with LPS and IFN-γ, LPGs were capable to alter the production of NO or IL-10. LPG from L. braziliensis has a dose-dependent effect in activated macrophages reducing the production of NO. On the other hand, LPG from L. amazonensis decrased the production of IL-10 by activated macrophages. In spite of these effects, the studied LPGs were not capable to modify the expression of molecules involved in the activation, presentation and cellular migration of macrophages. TLR2 does not seem to be required for observed effects. Our work contributes for the elucidation of the complex mechanisms that involve the immune response of the host and consequently the cure or resistance in Leishmania infections.

ASSUNTO(S)

- - ciencias biologicas

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