Novel chimeric genotype 1b/2a hepatitis C virus suitable for high-throughput screening.

Area of Science:

• Virology
• Hepatology
• Drug Discovery

Background:

• Hepatitis C virus (HCV) research faced challenges due to the lack of cell culture systems producing infectious viral particles.
• Recent advancements have led to the establishment of such systems, but their application in HCV drug screening remains underexplored.

Purpose of the Study:

• To develop and validate a novel infectious cell culture system for hepatitis C virus (HCV) drug screening.
• To compare the efficacy of this new system against existing subgenomic replicon systems in identifying antiviral compounds.

Main Methods:

• Generation of two monocistronic, chimeric full-length HCV genotype 1 genome molecules with a Renilla luciferase reporter.
• Transfection of cells, assessment of viral RNA replication, production of infectious viral particles, and infectivity blocking with anti-CD81 antibody.
• Pilot high-throughput screening of 900 compounds using both the new infectious system and a genotype 2a subgenomic replicon system.

Main Results:

• The chimeric HCV RNAs replicated efficiently and produced infectious viral particles in naïve Huh7.5 cells.
• Viral infectivity was confirmed and could be blocked by antibodies targeting the entry cofactor CD81.
• The infectious system identified 78 compounds missed by the subgenomic replicon system, suggesting broader inhibitor targeting capabilities.

Conclusions:

• The developed infectious HCV system is a versatile tool for identifying novel HCV inhibitors.
• This system can identify compounds targeting viral structural proteins and other life cycle steps missed by subgenomic replicon systems.
• The new system significantly advances HCV drug screening and discovery efforts.