(a) Mortality curves of wild-type BALB/c (◊, n = 12) and nude mice (▪, n = 12) after infection with 4 × 105 PFU MHV-A59. (b) Liver virus titers were determined at day 2 (P = 0.051) and day 4 (P = 0.925) after infection (n = 11). (c) TNF and IFN-γ concentrations in serum were determined at day 2 after infection (pool of 14–16 mice in each group from various experiments). Horizontal bars indicate the median values. Statistical comparisons were significant. **P < 0.01, by t-test.