AVALIAÇÃO DA UTILIZAÇÃO DE Lactobacillus delbrueckii UFV H2b20 COMO ADJUVANTE NA VACINAÇÃO CONTRA Leishmania braziliensis
One of the greatest challenges in the formulation of a vaccine against Leishmaniaparasites is the discovery of an adjuvant capable of enhancing the efficacy of the vaccine.Lactobacillus delbrueckii UFV H2b20 presents an immunomodulatory effectalready known in mice where it induces IL-12, IFN-and TNF-production in vitro, andincreases the clearance of pathogenic Escherichia coli in these animals. In mononuclearcells of the human peripheral blood of healthy volunteers, it induced the IL-12 productionIFN-and TNF-and stimulated the activation of effectors mechanisms of the innateimmunity, leading to the differentiation of naive T lymphocytes in Leishmaniaamazonensis specific Th1 lymphocytes.In this work, we decided to verify the capacity of the Lact delbrueckii to protectmice BALB/c against infection for Leishmania braziliensis, acting, thus, as an adjuvantinductor of a response that would control this parasite. It was verified that Lact delbrueckiiinduced the production, in vitro, of high levels of IL-12, IFN-and TNF-for splenocytesfrom mice BALB/c. However, when inoculated in the presence of L. braziliensis antigen,this bacterium was not able to induce protection in the mice against the inoculation ofinfective forms of this parasite. This result could be explained by the concomitant inductionof IL-10 by Lact delbrueckii, that could cause a suppression of the protective response.We also decided to isolate the molecule that was responsible for the induction of theIL-12 production by the Lact delbrueckii. For this, an extract of the cell wall of thisbacterium was prepared. This extract induced IFN- , in vitro, in a peculiar and distinct wayto the complete bacterium. The analysis of this extract demonstrated that the probableimmunomodulatory molecule may be a low molecular weight carbohydrate.These results demonstrate the importance of more detailed studies with Lact.delbrueckii and other probiotic bacteria in order to characterize its distinct componentsinvolved in the induction of determined cytokines.
Advisor:Luis Carlos Crocco Afonso; Célia Alencar de Morais; Ana Paula Salles Moura Fernandes
School:Universidade Federal de Ouro Prêto
Source Type:Master's Thesis
Date of Publication:07/18/2005