Fig 5.

T3D^C S1 coding sequences segregate with resistance to protease-mediated loss of infectivity. Purified virions of T3D^F, rsT3D^F/T3D^CS1-77, rsT3D^F/T3D^CS1-1234, and rsT3D^F/T3D^CS1 at a concentration of 5 × 10¹⁰ particles/ml were treated with either chymotrypsin (A) or neutrophil elastase (B) at 37°C. Viral titers before and after treatment were determined by plaque assay using L929 cells. Changes in viral infectivity are expressed as the ratio of log₁₀ viral titers at each treatment time relative to mock treatment. Results are shown from a representative experiment of three performed.