Dual effect of Lutzomyia longipalpis saliva on Leishmania braziliensis infection is mediated by distinct saliva-induced cellular recruitment into BALB-c mice earReportar como inadecuado




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BMC Microbiology

, 13:102

Microbe-host interactions and microbial pathogenicity

Abstract

BackgroundLeishmania parasites are transmitted to their vertebrate hosts by infected Phlebotomine sand flies during the blood meal of the flies. Sand fly saliva is known to enhance Leishmania spp. infection, while pre-exposure to saliva protects mice against parasitic infections. In this study, we investigated the initial inflammatory leucocyte composition induced by one or three inocula of salivary gland extract SGE from Lutzomyia longipalpis in the presence or absence of Leishmania braziliensis.

ResultsWe demonstrated that inoculating SGE once SGE-1X or three times SGE-3X, which represented a co-inoculation or a pre-exposure to saliva, respectively, resulted in different cellular infiltrate profiles. Whereas SGE-1X led to the recruitment of all leucocytes subtypes including CD4 T cells, CD4CD25 T cells, dendritic cells, macrophages and neutrophils, the immune cell profile in the SGE-3X group differed dramatically, as CD4 T cells, CD4CD25 T cells, dendritic cells, macrophages and neutrophils were decreased and CD8 T cells were increased. The SGE-1X group did not show differences in the ear lesion size; however, the SGE-1X group harbored a higher number of parasites. On the other hand, the SGE-3X group demonstrated a protective effect against parasitic disease, as the parasite burden was lower even in the earlier stages of the infection, a period in which the SGE-1X group presented with larger and more severe lesions. These effects were also reflected in the cytokine profiles of both groups. Whereas the SGE-1X group presented with a substantial increase in IL-10 production, the SGE-3X group showed an increase in IFN-γ production in the draining lymph nodes. Analysis of the inflammatory cell populations present within the ear lesions, the SGE-1X group showed an increase in CD4FOXP3 cells, whereas the CD4FOXP3 population was reduced in the SGE-3X group. Moreover, CD4 T cells and CD8 T cells producing IFN-γ were highly detected in the ears of the SGE-3X mice prior to infection. In addition, upon treatment of SGE-3X mice with anti-IFN-γ monoclonal antibody, we observed a decrease in the protective effect of SGE-3X against L. braziliensis infection.

ConclusionsThese results indicate that different inocula of Lutzomyia longipalpis salivary gland extract can markedly modify the cellular immune response, which is reflected in the pattern of susceptibility or resistance to Leishmania braziliensis infection.

KeywordsPhlebotomines saliva Lutzomyia longipalpis saliva Leishmania braziliensis Inflammatory leucocytes Cytokines Immunoregulation AbbreviationsSGE-1XSalivary gland extract inoculated once

SGE-3XSalivary gland extract inoculated three times.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2180-13-102 contains supplementary material, which is available to authorized users.

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Autor: Vanessa Carregaro - Diego Luis Costa - Claudia Brodskyn - Aldina Maria Barral - Manuel Barral-Netto - Fernando Q Cunha -

Fuente: https://link.springer.com/







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