Hepatitis C virus cell-cell transmission in hepatoma cells in the presence of neutralizing antibodies.
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.


CONCLUSIONS
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.
Timpe
Jennifer M
JM
Institute for Biomedical Research, University of Birmingham, Birmingham, United Kingdom.
Stamataki
Zania
Z
Jennings
Adam
A
Hu
Ke
K
Farquhar
Michelle J
MJ
Harris
Helen J
HJ
Schwarz
Anne
A
Desombere
Isabelle
I
Roels
Geert Leroux
GL
Balfe
Peter
P
McKeating
Jane A
JA
D000914:Antibodies, Viral / Q000502:physiology; D015703:Antigens, CD / Q000502:physiology*; D062445:Claudin-1; D006367:HeLa Cells; D016174:Hepacivirus / Q000276:immunology / Q000502:physiology*; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D011991:Receptors, Virus / Q000502:physiology; D060225:Tetraspanin 28
D000914:Antibodies, Viral; D015703:Antigens, CD; C554798:CD81 protein, human; C568108:CLDN1 protein, human; D062445:Claudin-1; D008565:Membrane Proteins; D011991:Receptors, Virus; D060225:Tetraspanin 28