Viral dynamics of persistent hepatitis C virus infection in high-sensitive reporter cells resemble patient's viremia

Abstract

Background: Hepatitis C virus (HCV) infection has a high persistence rate in patients. Although immune cells play a central role in determining the outcomes of HCV infection, the liver is crucial in controlling HCV activity from acute to chronic stages. This investigation grew HCV from a long-term cell culture, and provided an experimental model for studies on HCV persistence in hepatocytes. Methods: Huh7.5 cells implanted with the NS3/4 protease-based secreted alkaline phosphatase (SEAP) reporter were infected with JFH-1 HCV (moiety of infection = 0.01) and incubated for over 130 days. Results: The viral activity was obtained by sampling supernatant continuously for SEAP activity measurement. Combined with extracellular and intracellular HCV-RNAs and viral infectivity assays, the experimental results exhibited in vitro viral dynamics resembling the patients' viremia pattern from acute to chronic infections. The HCV in acute infection comprised exponential accumulation (week 1), plateau (week 2), declining production (weeks 3–4) and silencing (weeks 5–14) phases, and were then reactivated at the onset of chronic infection (after week 15). The HCV-infected cells grew more slowly than the mock controls, and exhibited a prominent decrease of cell growth rate and increase of early apoptosis in the declining-to-silencing phase transition, suggesting that fitness selection might occur as the infected cells moved across the boundary of active to occult viral activity. Conclusion: Cultivated HCV in the highly sensitive NS3/4-based SEAP reporter cells could establish persistence, which might mimic the viral dynamics from acute to chronic infections in hepatitis C patients. Keywords: Acute and chronic infections, Apoptosis, Hepatitis C virus, Long-term culture, Secreted alkaline phosphatase reporter