Figure 3.

Infection with VV-p40 triggers disease in persistently infected B10.BR but not in C57BL/10 mice. Symptomless, persistently infected B10.BR (A and B) or C57BL/10 (C and D) mice were superinfected with various recombinant vaccinia viruses as indicated and observed for a maximum of 12 days after superinfection. (A and C) Health status. Mice were examined and weighed daily. Severity of disease was scored on an arbitrary scale as described in Materials and Methods. (B and D) Degree of CNS inflammation. Bars indicate the percentage of animals with symptoms. Scoring was on an arbitrary scale from 0 to 3 as described. The percentage of animals with severe encephalitis (scores 2 and 3) is depicted. Persistent BDV infection of all animals was confirmed by immunohistochemical staining of the p40 antigen in CNS cells on paraffin-embedded brain sections.