Schwann cell remyelination and recurrent demyelination in the central nervous system of mice infected with attenuated Theiler's virus

Theiler's murine encephalomyelitis virus (TMEV) infection produces a chronic demyelinating disease in mice, and myelin breakdown appears to be immune-mediated. By using an attenuated TMEV strain, WW virus, to infect mice, the course of the disease was slowed and the severity of the inflammatory and glial responses was reduced. In this circumstance, most of the demyelinating lesions showed extensive remyelination, predominantly by Schwann cells. In addition, it was demonstrated that there was recurrent demyelinating activity in the central nervous system (CNS) of infected animals. It is suggested that the rapidity and intensity of demyelinating lesions may influence the potential for remyelination and that Schwann cell participation may be a more important mechanism of myelin in repair than it is now thought to be. The fact that there is recurrent demyelination in TMEV infection increases its relevance as an experimental animal model for multiple sclerosis.