Experimental patterns related to multiple sclerosis pathology.

In the history of experimental demyelination, allergic encephalomyelitis (EAE) is the most impressive experimental demyelinating disease based on an immunological mechanism. The evolution of the neuropathological process of chronic EAE is very close to that of chronic Multiple Sclerosis. On the other hand experimental inoculation of different viruses can induce various types of demyelination depending on the main target of the virus and the host response, this latter being conditioned by the age, the mechanism of immunity and the persistence of the virus in the brain. The demyelination can be induced by a viral persistent infection primarily affecting oligodendrocytes (CDV, JHM hepatitis virus) or acting through an immunomediate response against myelin (Visna, Theiler virus, human conventional viruses). The experimental demyelinating models show that also in Multiple Sclerosis a viral etiology could be the starting point of a demyelinating process based on a immunologically mediated mechanism.