CORRELATION OF SPECIFIC IMMUNITY AND DISEASE ACTIVITY IN EXPERIMENTAL AUTOIMMUNE ENCEPHALOMYELITIS

SEGER J.(1), ZORZELLA S. F. G.(1), PELIZON A. C.(1), MARTINS D. R.(1), BRANDÃO I. T.(2), SANTOS JR, R. R.(2), SILVA C. L.(2), SARTORI A.(1)

(1)Department of Microbiology and Immunology, IB, UNESP, Botucatu, SP, Brazil; (2)Department of Biochemistry and Immunology, FMRP, USP, Ribeirão Preto, SP, Brazil

Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease of the brain and spinal cord that is mediated by CD4+ T lymphocytes specific to myelin components. EAE is widely used as an experimental model for human multiple sclerosis. The Lewis strain of rats is very susceptible to induction of EAE by inoculation of purified myelin suspended in Complete Freund’s adjuvant (CFA). The purpose of the present study was to investigate the correlation between disease activity and specific immunological parameters. Female Lewis rats (4–6 weeks old) were immunized, in the left footpad, with 100mL of an emulsion containing 50mg of MBP associated with 50 ml of ACF (Incomplete Adjuvant plus 5mg/ml of M. butyricum). Non immunized rats were used as a control group. Animals were daily evaluated for both, clinical score and weight. Rats were submitted to euthanasia during acute and recovery phases, characterized by high clinical scores and absence of clinical signs, respectively. Specific anti-myelin antibody levels and cytokine (IFN-g and TNF-a) production induced by myelin and ConA were evaluated. All immunized animals developed the disease and showed a significant lost in weight. Anti-myelin antibody levels (IgG1 and IgG2b) increased during recovery phase. On the other hand, production of IFN-g and TNF-a by spleen and lymph nodes stimulated with myelin were higher in the acute phase of the disease. Differences in TNF-a levels correlated better with disease activity. These results show clear differences in immunity to myelin during distinct phases of EAE.

KEY WORDS: experimental autoimmune encephalomyelitis, IFN-g, TNF-a, Lewis rats

FINANCIAL SUPPORT: CNPq and FAPESP

CORRESPONDENCE TO:

Alexandrina Sartori, Departamento de Microbiologia e Imunologia do Instituto de Biociências de Botucatu, UNESP, Caixa Postal, 510, CEP 18618-000, Botucatu, SP. Email: sartori@ibb.unesp.br