| Grant number: | 09/11576-5 |
| Support Opportunities: | Scholarships in Brazil - Master |
| Start date: | March 01, 2010 |
| End date: | February 29, 2012 |
| Field of knowledge: | Agronomical Sciences - Veterinary Medicine - Animal Pathology |
| Principal Investigator: | Valéria Marçal Felix de Lima |
| Grantee: | Mariana Macedo Costa de Andrade |
| Host Institution: | Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil |
Abstract Visceral leishmaniasis (VL) is a disease caused by the intracellular parasite for the Leishmania genus that affects humans and several animal species. The dog is one of the main urban reservoirs of the parasite because it plays a central role in the transmission cycle to humans by sandflies. Studies about the immune response in dogs with visceral leishmaniasis have demonstrated that protective immunity is associated with the immune response of the cell type, while disease progression is associated with the humoral response and IL-10 and TGF-² production. These cytokines induce the macrophages deactivation and have the potential to disable the host defense against Leishmania spp. leading to infection visceralization. The aim of this study was to evaluate the regulatory T cells (Treg) producing IL-10 and TGF-² in blood and spleen samples from dogs naturally infected by Leishmania spp. and correlate to the parasite load and histopathology. Five healthy dogs and twenty-nine dogs with clinical visceral leishmaniasis manifestations, and seropositivity for anti-Leishmania antibodies were included in the study group. The real-time PCR was used to quantify the parasite load and infection confirmation with Leishmania spp. The regulatory CD4 T cells producing IL-10 and TGF-² quantification was performed by flow cytometry. The unpaired t test was used to compare the percentage of Treg cells producing IL-10 and TGF-² between infected and healthy dogs. The Mann-Whitney test was used to compare the percentage of IL-10 and TGF-² in blood and spleen of the dogs with VL. The Spearman correlation was used to compare the percentage of IL-10 and TGF-² produced by Treg cells with the parasite load and the histological findings. Results were considered significant when the p <0.05. There was an increased production of IL-10 by Treg cells in the spleen from dogs naturally infected by Leishmania spp. while it was observed a decrease number of these cells in these dogs compared to healthy dogs. There was no correlation between parasite load and the percentage of splenic Treg cells producing IL-10 and TGF-² and there was no correlation between this cell population and histopathological findings. These results suggest that Treg cells are important sources of IL-10 in the spleen participating in the modulation of the immune response | |
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