Almost all people with MS, even children, have evidence of a prior Epstein-Barr virus (EBV) infection. Our working hypothesis is that there is an unknown factor or “trigger” that interacts with EBV to initiate the events that lead to MS. Tisch MSRCNY is investigating the consequences of EBV infection in the brain with an in-vitro infection model involving the use of peripheral B-cells infected with EBV that, at a later time, are co-cultured with glial and neuronal cell types. The analysis of the glial response to EBV-infected will help identify novel pathways contributing to MS pathogenesis.