Establishment of serum derived infectivity coculture model for enhancement of hepatitis C virus replication in vitro.

Background And Aims: Although HCV is one of the major health problems worldwide with the highest prevalence of genotype 4a in Egypt, it is poorly understood because of the limitations of having a robust in vitro model that allows the investigation and understanding of viral pathogenesis and life cycle. Genomic replicons for HCV are widely used and proved to have strong replication efficiency in cell culture, however, they are not able to produce infectious particles to enable the investigation of the whole viral life cycle and they mostly represent few sub-genomic classes for HCV. Hence, Genotype specific replication system is necessary to address specific sub-genomic phenotypes related to Hepatitis C pathogenicity.

Methods: In this study we attempt to develop a sustainable co-culture model, which potentially provides essential route of infection for HCV by using HCV-positive sera from infected patients. In this novel in vitro model, we tested the viral replication in co-cultured Huh 7.5 and HepG2 cells in order to sustain full viral replication cycle. We used high viral load serum of HCV-infected patients (10 × 106 to 20 × 106 IU/ml) as a source for HCV particles to infect co-cultured cells for 7 days.

Results And Conclusions: Viral replication capacity was increased 3-5 folds in the coculture condition compared to the individual cell lines, which indicates an improvement to viral infectivity in vitro.

Significance Statement: This novel coculture system represents a new in vitro model that will help study the underlying mechanisms of HCV pathogenicity.