Avaliação de proteínas de Leishmania spp. sob a forma de Antígenos Recombinantes como marcadores imunológicos na Leishmaniose Visceral

Abstract

Visceral leishmaniasis (VL) is a potentially fatal disease, in which treatment is toxic and/or presents high costly. The protection against Leishmania infection is associated with the development of Th1- type immunity, being based on the production of cytokines, such as IFN- gama and IL-12, by peripheral blood mononuclear cells (PBMCs) of the infected mammalian hosts. In the present study, five parasite proteins, namely IgE-dependent histamine releasing factors (HRF) and four hypothetical proteins (LiHyD, LiHyV, LiHyT and LiHyp6), when in their recombinant formats, were used to evaluate the cellular and humoral response developed, by using sera samples and stimulated PBMC culture supernatants from VL patients, before and after the treatment against the disease. In the results obtained evaluating the cellular response, when PBMCs were stimulated with the rHRF, rLiHyD and rLiHyT proteins, higher IFN- levels and lower IL-10 production were found in the treated patients. Evaluating the antibody production, a higher production of rHRF, rLiHyD and rLiHyT-specific IgG2 isotype was found in sera from treated patients, when compared to the levels of the IgG1 antibody. Additionally, evaluating the diagnostic efficacy of the recombinant molecules, rHRF, rLiHyD and rLiHyT proteins were those presenting better sensitivity and specificity values in the serological assays to diagnose VL. The rLiHyV and rLiHyp6 proteins showed a mixed production of IFN-gama and IL-10, besides worse results in the serological assays. In conclusion, this work indicates that the evolution of the treatment of VL can be associated with the development of Th1-type cell response, based on the production of IFN-gama, and denotes the potential use of the rHRF, rLiHyD and rLiHyT proteins as possible biomarkers for the diagnostic evaluation and treatment against VL.