FIG. 4.

Protection against MCMV infection by RV7 vaccination requires viral replication and lymphocytes. (A) BALB/c mice were inoculated with 2 × 10⁵ PFU of RV7, UV-inactivated RV7, or wt tissue culture-passaged MCMV, or were mock vaccinated, on days 0 and 14 of experiments. On day 28, mice were challenged i.p. with either 10⁴ or 10⁵ PFU of sgMCMV. Four days later, spleens were harvested and the MCMV titer was determined. When spleen titer was not detected by plaque assay, the titer was arbitrarily fixed at 100, the limit of plaque assay sensitivity. Data were pooled from two separate experiments (a total of six mice per condition) and are shown as mean log titer ± SEM. (B) Mice of the indicated strains were vaccinated with 2 × 10⁵ PFU of RV7 s.c., or were mock vaccinated, on days 0 and 14 of the experiment and then challenged with 10⁴ PFU of sgMCMV i.p. on day 28 of the experiment. Four days later, spleens were harvested and the MCMV titer was determined. Data were pooled from two experiments, with six to seven mice per condition.