The Establishment Of Murine Experimental Autoimmune Encephalomyelitis Model And The Study Of Its Immunologic Mechanisms

ObjectiveMultiple sclerosis is an inflammatory and demyelinating disease of the central nervous system, which is characterized by the relapsing, deferment and high disability. Because the sample of MS is not easy to be obtained and exact pathogenesis remains unclear, it is necessary to establish animal model to study MS. In this study, to establish stable and reliable animal model with high incidence, we induced experimental autoimmune encephalomyelitis ( EAE ) models of C57BL/6 mice by myelin oligodendrocyte glycolprotein, MOG_35-55, and explore the immunologic mechanisms causing EAE, it is supposed to provide basis for the pathogenesis, prevention and therapy of MS. Methods1. Each mouse was immunized subcutaneously with 150μg or 300μg of MOG_35-55 emulsified in CFA containing 1.0mg BCG, and then immediately injected intraperitoneally with pertussis bacterium and again 2 days later. C57BL/6 mice received a booster immunization at day 6 in CFA without pertussis bacterium. The clinical symptoms, weight and histopathologic changes of the central nervous system ( CNS ) were observed.2. Responses of splenic T lymphocytes to MOG_35-55 were detected by methods of MTT, serum anti-MOG_35-55 antibodies levels were detected by indirect ELISA technique and serum interferon-γ( IFN-γ) concentrations were detected by antibody-sandwich ELISA method. Comparing them between EAE mice and normal mice, we explore the immunologic mechanisms causing EAE.Results1. The EAE group with 300μg MOG_35-55 developed the typical symptoms of EAE with the incidence of 100%, the highest clininal score is up to 5; the EAE group with 150μg MOG_35-55 developed the typical symptoms of EAE with the incidence of 80%, the highest clinical score is up to 3. The infiltration of inflammatory cells in brains and spinal cords and the demyelination of the white matter were observed throμgh HE staining, which of the group with 300μg MOG_35-55 is more obvious.2. T cells were stimulated with various concentrations of MOG_35-55. When T cells were stimulated with 0.5μg/ml, 2.5μg/ml, 5.0μg/ml of MOG_35-55, the stimulate index had a tendency to increase with the increase of the concentration; when they were stimulated with 15μg/ml, 25μg/ml, 50μg/ml, T cell proliferation was not increased.3. Production of anti-MOG_35-55 antibodies in serum of EAE correlated with the occurrence and development of disease. Serum anti-MOG_35-55 antibodies started to be positive at the beginning of the disease; they were highest at the peak of the disease; they gradually descended with the remission of the disease.4. Increase of serum interferon-γconcentrations correlated with the severity of EAE clinical signs.Conclusions1. The model construction of C57BL/6 was successful immunized with MOG_35-55 emulsified in complete Freund's adjuvant ( CFA ) and injected intraperitoneally with pertussis bacterium. They developed a chronic monophasic course. The model had a high incidence and its pathologic changes were close to those of multiple sclerosis ( MS ), so it might be an ideal model for the research of MS.2. It is supposed that the activity of T cell response to MOG_35-55 and the increases of anti-MOG_35-55 antibody and IFN-γlevels may play key roles in the onset of EAE. It is supposed to provide basis for the pathogenesis, prevention and therapy of MS.