Comparison of experimental data with models. (a) Fixed-MOI passages, with data (filled symbols, solid lines) and model (open symbols, dashed lines) and (b) fixed-volume passages. The data are from Fig. 1, and predictions from the model incorporate experimentally measured cell levels at each passage. The initial virus concentration (passage 1) for models is based on the measured stock virus titer, where we assume the stock virus was free of any DI particles or IE activity. Models all used parameters from Table 1.