FIG. 3.

s51 and s55 grow with equivalent kinetics in the brains of infected mice. Six-week-old female CD-1 mice were infected i.c. with 10³ PFU of s51 or s55. Mice were sacrificed by exsanguination at 12, 24, 48, 72, 96, 120, and 144 h postinfection and perfused with PBS (pH 7.4). The left hemisphere of each brain was removed and placed in three volumes of PBS (1% DCS, Ca²⁺-Mg²⁺). Samples were frozen and thawed before homogenization and titration by plaque assay on BHK-21 cells. Each data point represents the mean titer ± the standard error. ○, s51; ▴, s55. n = 6 to 12 animals for each time point from three pooled experiments.