IFNγ induces a wide range of effects on CNS cells, including macrophage activation, enhancement of leukocyte adhe-sion, release of TNF-α and other cytokines, and upregulation of MHC expression on microglia and macrophages (Munoz-Fernandez and Fresno, 1998) . We evaluated the role of IFNγ in protecting neurons from virus-induced injury after infection with Theiler's virus.