Timpe, J. M. et al. Hepatitis C virus cell-cell transmission in hepatoma cells in the presence of neutralizing antibodies. Hepatology 47, 17-24

Institute for Biomedical Research, University of Birmingham, Birmingham, United Kingdom.
Hepatology (Impact Factor: 11.06). 11/2007; 47(1):17-24. DOI: 10.1002/hep.21959
Source: PubMed


Hepatitis C virus (HCV) infection of Huh-7.5 hepatoma cells results in focal areas of infection where transmission is potentiated by cell-cell contact. To define route(s) of transmission, HCV was allowed to infect hepatoma cells in the presence or absence of antibodies that neutralize cell-free virus infectivity. Neutralizing antibodies (nAbs) reduced cell-free virus infectivity by >95% and had minimal effect(s) on the frequency of infected cells in the culture. To assess whether cell-cell transfer of viral infectivity occurs, HCV-infected cells were cocultured with fluorescently labeled naïve cells in the presence or absence of nAbs. Enumeration by flow cytometry demonstrated cell-cell transfer of infectivity in the presence or absence of nAbs and immunoglobulins from HCV(+) patients. The host cell molecule CD81 and the tight junction protein Claudin 1 (CLDN1) are critical factors defining HCV entry. Soluble CD81 and anti-CD81 abrogated cell-free infection of Huh-7.5 and partially inhibited cell-cell transfer of infection. CD81-negative HepG2 hepatoma cells were resistant to cell-free virus infection but became infected after coculturing with JFH-infected cells in the presence of nAb, confirming that CD81-independent routes of cell-cell transmission exist. Further experiments with 293T and 293T-CLDN1 targets suggested that cell-cell transmission is dependent on CLDN1 expression. Conclusion: These data suggest that HCV can transmit in vitro by at least two routes, cell-free virus infection and direct transfer between cells, with the latter offering a novel route for evading nAbs.

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    • "Further studies have demonstrated that HCV internalization requires the clathrinmediated endocytosis (Blanchard et al., 2006) and that the acidic pH of the early endosomes is essential to trigger fusion and uncoating (Meertens et al., 2006). The virus can also use a neutralizing antibody resistant transfer called cell-cell transmission (Timpe et al., 2008; Witteveldt et al., 2009). "
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    • "In addition to cell-free virus entry, where CD81 has been described as an essential factor [12], [14], [15], [16], [17], [30], [31], HCV uses direct cell-cell transfer to infect neighbouring cells and persist in the presence of virus-neutralizing antibodies [10]. This process also seems to require several HCV host factors including CD81, SR-BI, CLDN1, OCLN, EGFR, EphA2 and NPC1L1 [10], [25], [32], [33] but has been less extensively characterized than cell-free entry. Although a CD81-independent route of HCV spread has been described [10], [34], [35], the exact role of CD81 in viral cell-cell transmission remains unknown. "
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