TABLE 1.

Time course of SV40 wt and F98A mutant production in BSC40 monkey cells^a

Time (hpi)	wt titer	F98A titer (PFU)
6	2.3 × 10e3	3.0 × 10e3
24	2.6 × 10e3	2.8 × 10e3
48	1.4 × 10e5	4.1 × 10e4
72	1.4 × 10e7	2.2 × 10e6
96	8.3 × 10e7	2.0 × 10e7

^aConfluent monolayers of BSC40 cells were infected with wt SV40 (strain 776) or the F98A mutant at a multiplicity of infection of 5. The infected dishes were monitored daily for cytopathic effect. At various times postinfection, the infected dishes were treated to three freeze-thaw cycles and stored at −20°C. Virus titers were determined by plaque assay on BSC40 cells (84).