Drescher, Kristen M.

AbstractTheiler's murine encephalomyelitis virus causes a chronic demyelinating disease in susceptible strains of mice that is similar to human multiple sclerosis. Several nonmajor histocompatibility complex–linked genes have been implicated as determinants of susceptibility or resistance to either demyelination or virus persistence. In this study, we used linkage analysis of major histocompatibility complex identical H-2d (DBA/2J × B10.D2) F2 intercross mice to identify loci associated with susceptibility to virus-induced demyelinating disease. In a 20-cM region on chromosome 14, we identified four markers, D14Mit54, D14Mit60, D14Mit61, and D14Mit90 that are significantly associated with demyelination. Because two peaks were identified, one near D14Mit54 and one near D14Mit90, it is possible that two loci in this region are involved in controlling demyelination.

Abstract TGF-β2 is a potent immunoregulatory mediator that influences B cell, T cell, and macrophage function. To test whether this cytokine alters pathology in a model of virus-induced demyelinating disease, we treated SJL/J mice with TGF-β2 either before or after infection with Theiler’s murine encephalomyelitis virus. Treatment continued three times weekly through day 35 postinfection. TGF-β2 administration resulted in significantly smaller lesions and fewer virus Ag-positive cells in the spinal cords of infected SJL/J mice. Mice treated with TGF-β2 had similar levels of virus-specific IgG as infected, control-treated mice. TGF-β2 administration significantly increased the level of non-virus-specific activated CTLs, but had no effect on virus-specific CTLs. TUNEL revealed a decrease in the number of apoptotic nuclei in the spinal cord white matter of mice treated in vivo with TGF-β2. Immunostaining with an Ab to F4/80 revealed that TGF-β2-treated mice had significantly fewer F4/80-positive cells in the white matter of the spinal cord as compared with infected control-treated mice. These data suggest that TGF-β2 may control virus-induced demyelination via an immunomodulatory mechanism that reduces macrophage infiltration.