Citation

Viral infection has been identified as the most likely environmental trigger of multiple sclerosis (MS). There are conflicting data regarding the role of cytomegalovirus (CMV) in MS pathogenesis. We utilised experimental autoimmune encephalomyelitis (EAE)-resistant BALB/c mice and murine cytomegalovirus (MCMV), the murine homolog of CMV, to examine the mechanism by which viral infection enhances autoimmune neuroinflammation. Mice subjected to latent neonatal MCMV infection developed the typical characteristics of EAE. Similar to MS, the MCMV-infected EAE-induced mice developed infiltrates in the central nervous system (CNS) composed of similar percentages of CD4+ and CD8+ T cells. The influx of both Th 1 and Th 17 cells into the CNS of MCMV- infected EAE-induced mice was observed. Interestingly, the development of autoimmune neuroinflammation after latent MCMV infection was accompanied by a significant influx of Tc17 cells (CD8+IL-17+ and CD8+RoRt+) but not Tc1, cells. Our results suggest that latent MCMV infection affects the development of inflammatory lymphocytes that exhibit encephalitogenic potential, thereby mediating increased CNS pathology following EAE induction, and that CMV represents a possible environmental factor in the pathogenesis of MS and other autoimmune diseases