FIG. 4.

Growth of HAV in MMH-D3 cells cultivated without EGF. MMH-D3 cells grown under optimal conditions (with IGF II and EGF [complete medium]), without IGF II [(−) IGF II], without EGF [(−) EGF], or without both growth factors [(−) IGF II/EGF] were infected with HAV PI at an MOI of a 2 TCID₅₀/cell. At 24 h postinfection, cells were washed three times, split 1:3, and grown at 35°C in a CO₂ incubator. Cells were split 1:3 weekly; approximately one-third of the remaining cells were subjected to three freeze-thaw cycles, cellular debris was pelleted, and the HAV in the supernatant was titrated as described in the legend to Fig. 1. Error bars, standard deviations.