Infectious Hepatitis C Virus Pseudo-particles Containing Functional E1–E2 Envelope Protein Complexes

TLDR

Hepatitis C virus research has been limited by the absence of a cell culture system that supports viral replication. The authors aimed to create infectious pseudo‑particles displaying functional HCV E1–E2 glycoproteins to study receptor usage. They incorporated a GFP marker into retroviral or lentiviral cores, enabling rapid, reliable infectivity assays mediated by the HCV envelope proteins. The resulting pseudo‑particles infected primary hepatocytes and hepatocarcinoma cells, required both E1 and E2, were neutralized by patient sera and anti‑E2 antibodies, showed that LDLr and CD81 alone are insufficient for entry, and thus recapitulate early HCV infection, offering a platform for antiviral development.

Abstract

The study of hepatitis C virus (HCV), a major cause of chronic liver disease, has been hampered by the lack of a cell culture system supporting its replication. Here, we have successfully generated infectious pseudo-particles that were assembled by displaying unmodified and functional HCV glycoproteins onto retroviral and lentiviral core particles. The presence of a green fluorescent protein marker gene packaged within these HCV pseudo-particles allowed reliable and fast determination of infectivity mediated by the HCV glycoproteins. Primary hepatocytes as well as hepato-carcinoma cells were found to be the major targets of infection in vitro. High infectivity of the pseudo-particles required both E1 and E2 HCV glycoproteins, and was neutralized by sera from HCV-infected patients and by some anti-E2 monoclonal antibodies. In addition, these pseudo-particles allowed investigation of the role of putative HCV receptors. Although our results tend to confirm their involvement, they provide evidence that neither LDLr nor CD81 is sufficient to mediate HCV cell entry. Altogether, these studies indicate that these pseudo-particles may mimic the early infection steps of parental HCV and will be suitable for the development of much needed new antiviral therapies.