Growth of mutant and revertant MCMVs in BALB/c mice following i.p. or i.n. inoculation. (A) Five BALB/c mice per group were inoculated i.p. with 5 × 105 PFU of tissue culture-derived virus, and resultant viral titers in the livers, kidneys, and spleens 4 days postinoculation, or in the salivary glands 10 days postinoculation, are shown. Titers represent the means of the log10 PFU/organ values, with the standard deviations (SD) being shown by error bars. Values above each bar indicate the fold reductions of the nonlogarithmic mean titers (i.e., PFU/organ) of that group relative to the corresponding K181-infected controls. The subscript 0 indicates that in at least one organ in that group, virus was undetectable, and that the titer of that organ was set to the limit of detection for calculation purposes. (B) Day 4 spleen and day 10 salivary gland titers of four mice per group inoculated i.p. with K181, rΔM83, ΔM83, or ΔM83-2 as described for panel A. (C) MCMV titers in the lungs and salivary glands of four mice per group 14 days following inoculation i.n. with 1.5 × 105 PFU of virus.