Figure 8. Production of infectious HCV in cell culture.

Limiting dilution assays were performed to quantify the amount of infectious HCVcc particles in the cell culture supernatant, measured as 50% tissue culture infectious dose per milliliter (TCID₅₀/ml). HCV infectivity accumulated until 72 h, after which a decline occurred that parallels the previously described decrease in HCV RNA levels [17]. The reason for these decreases is unclear, but may be related to a decrease in the number of cells capable of producing high levels of virus.