Fig. 3.

Analysis of multiple-step growth of different mutants and Towne_BAC in HFF (A) [multiplicity of infection (moi) = 0.05], RPE cells (B) (moi = 0.25), and HMVEC (C) (moi = 0.05). (D) Comparison of the growth properties of 15 mutants in these three cell types with those of Towne_BAC. +++, Peak titer similar to that of Towne_BAC; +++++, peak titer at least 100 times higher than that of Towne_BAC; +, peak titer at least 100 times lower than that of Towne_BAC. Cells were infected with each virus, and at different time points postinfection, cells and culture media were harvested and sonicated. The viral titers were determined by plaque assays on HFF (13). The values of the viral titer represent the average obtained from triplicate experiments. The standard deviation is indicated by the error bars.