Virus growth in EL-4 murine T cells (A) and J774 murine macrophages (B) after infection with SC35 and SC35M at a multiplicity of infection of 10−2. At time points 24, 48, 72, and 120 hours p.i., supernatants of infected cells were collected, and virus titers were determined using plaque assay. The figure shown is representative of two independent experiments.