Our findings highlight two very important concepts: 1) a classically non-demyelinating strain can develop fulminant hemorrhagic demyelination by intravenous administration of an immunodominant peptide recognized by CD8 T cells; and 2) this hyperacute model of hemorrhagic demyelination is the first TMEV-induced murine model of AHLE. The gene discussed is CD8A; the disease is acute hemorrhagic leukoencephalitis.