Figure 1.
Weight loss of mice infected with PBS, SC35, and SC35M. Groups of 10 mice were infected intranasally with 106 PFU of recombinant SC35 or SC35M, respectively. Animals were weighed daily and observed for illness for 14 days (A). Transcription and replication activity in murine lung cells (LA-4). LA-4 cells were infected with SC35 or SC35M and as a control with PBS using an multiplicity of infection 2. At 6 hours p.i., total RNA was isolated, and primer extension assays were performed as described in Materials and Methods (B). Error bars indicate SD of three independent experiments.