The role of CD4+ T cells in C57BL/6 mice is restricted to the earlier induction phase of ECM, as antibody depletion of these cells prevented ECM if performed 4 days post-infection (p.i.)but not 6 days p.i.; in contrast, CD8+ T-cell depletion at the later time point, just 1 day before the onset of neurological symptoms, completely abrogated ECM death (Belnoue et al, 2002). This evidence concerns the gene CD8A and infection.