Figure 5.

Low RV infectivity can be partially overcome by increasing virus titers, prolonged infection duration and/or repeated infections. (A) Subconfluent U251 cells were infected with twofold serially diluted RV-RB supernatant for 8 h. The cells were selected with blasticidin S resistance marker (BSD) for 5 days and stained with crystal violet (a), followed by quantitative measurements (b). Each assay condition was done in triplicate, and representative results are shown. (B) Subconfluent U251 cells were infected with the fixed titer of RV-RB supernatant for 4, 8 or multiple rounds of 4 h infection (2 ×, 3 × and 4 ×). The cells were selected with BSD for 5 days and stained with crystal violet (a), followed by quantitative measurements (b). Each assay condition was done in triplicate, and representative results are shown.