Efeitos do Lactococcus lactis produtor de HSP65 na medula espinhal de camundongos com encefalomielite autoimune experimental

Abstract

Multiple sclerosis is an autoimmune disease associated with a dysfunctional operation of the immune system of an individual. This is usually mediated by genetic factors and influenced by environmental, and leads to destruction of target cells of the central nervous system by inflammatory cells. Multiple sclerosis is studied by a model called experimental autoimmune encephalomyelitis (EAE) in which an immunization with antigens derived from the myelin sheath induces a specific immune response inducing disease manifestations similar to those in humans. Using the strategy of oral tolerance induced by the continuous intake of a specific antigen protein in low doses, and the immunomodulatory properties of heat shock proteins, we conducted a study to better understand the effect of the continuous feeding of HSP65-producing Lactococcus lactis in preventing EAE. In previous studies, our group has confirmed the efficacy of this modulatory mechanism and studied various immunological parameters in secondary lymphoid organs. Herein, we focused the analysis in the events taking place at the spinal cord and in cell migration. After 5 days of oral treatment with either HSP65-producing L.lactis (HSP65+EAE) or water only as a control (water + EAE), C57BL / 6 mice were immunized with MOG and CFA for disease induction. On days 4, 10 and 14 after immunization, animals were killed. We observed a decreased in inflammatory infiltrated and injured areas on spinal cord 14 days after the immunization (time point of the highest clinical score of EAE) only in HSP65 + EAE group. A study of regulatory CD4+ T lymphocytes showed that, at this time point, a higher frequency of Foxp3- LAP+ cells occurs in HSP65 + EAE group. This result indicates a greater importance of this cellular phenotype in preventing EAE. Regarding the parameters related to cell migration studied in the 4th day after EAE induction, we studied the chemokines receptors CCR6 and CXCR3, which contribute to the induction and suppression of disease, respectively. They were analyzed in the spleen, mesenteric and inguinal lymph nodes. In general, we observed a reduced frequency of effector cells expressing CCR6 and an increased frequency of T cells expressing CXCR3 in HSP65 + EAE group. We also evaluate, on the 14th day, the integrins α4β1 and αLβ2, both important for disease induction. We observed a reduction in the XVIII frequency of CD4+ effector T lymphocytes expressing α4β1 in spleen. Analysis of these results suggests that ingestion of L.lactis producing of HSP65 leads to many effects in the spinal cord of mice, which may be involved in the prevention of EAE. Although this work cannot define the mechanism of HSP65 effect yet, the possibilities presented are plausible and should be further studied.