Activation of T cells in experimental autoimmune encephalomyelitis and multiple sclerosis

Aims. In this study we describe the main findings from research into the autoreactive process triggered by activated T lymphocytes, which are generated in the peripheral compartment and then migrate towards the central nervous system (CNS) in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE)-its animal model. Method The different strategies that have been developed to date for the immunological treatment of MS have been designed to intervene in the pathogenic process of the disease by blocking the activation of T cells and B cells with specific antigens, interfering with immunological effector mechanisms and inhibiting the migration of lymphocytes towards the CNS. The cause of the inflammatory response in MS has still not been defined, but the findings from EAE studies and inpatients with MS suggest that the disease has an autoimmune aetiology involving autoreactive T cells which are specific for antigens in the myelin membrane. To activate these cells at least two cues are needed during antigen recognition and later the T CD4+ lymphocytes are differentiated in two subpopulations, Th1 and Th2, which differ in the pattern of secretion of cytosines depending on the stage of the disease process. The progressions of EAE and MS give rise to changes in the primary and secondary self-reactive responses of the T cells during the progression of the disease. Conclusion. The pathological immune mechanisms mediated by activated myelin-specific T lymphocytes play a key role in the progression and recuperation, as well as the mediation, of tissue damage during the course of MS and EAE.