FIG. 2.

Mortality, morbidity, and virus titers in mice infected with rJ2.2.6, rJ2.2.6^trunc, or rJ2.2.6^KO. Mice were infected with rJ2.2 (triangles), rJ2.2.6 (open circles), or rJ2.2.6^trunc or rJ2.2.6^KO (squares) and monitored for mortality (A), clinical disease (B), and weight loss (C). Groups of 6 rJ2.2-, 38 rJ2.2.6-, and 30 rJ2.2.6^trunc- or rJ2.2.6^KO-infected mice were used in these studies. (D) CNS virus titers were also determined. A total of 212 mice were used for this purpose. Significant increases in virus titers were detected in the CNS of rJ2.2.6-infected mice compared to mice infected with rJ2.2.6^trunc+KO (day 1.5, P = 0.38; day 3, P = 0.23; day 6, P < 0.01; day 7, P = 0.056; day 9, P < 0.001). Significant increases in virus titers were detected in the CNS of rJ2.2.6-infected mice compared to mice infected with rJ2.2 (day 7, P < 0.05; day 9, P < 0.005). Data for days 0 to 9 p.i. are shown in panels B, C, and D for the rJ2.2.6-infected mice because only 23% of mice survived past this time. The data for rJ2.2.6^trunc- and rJ2.2.6^KO-infected mice were combined, since mice infected with these viruses developed the same clinical disease. (E) RNA was harvested from the brains of mice infected with rJ2.2.6 (open bars; n = 3) or rJ2.2.6^KO (closed bars; n = 3) at each time point. The amount of N gene-specific RNA was quantified by real-time RT-PCR as described in Materials and Methods.