1156 THE RIBOSOMAL PROTEIN RACK1 IS A SPECIFIC HOST FACTOR REQUIRED FOR IRES-MEDIATED TRANSLATION OF HEPATITIS C VIRUS

Abstract

sensitive to HCV-clinical strains infection (HCVser), support the complete replication cycle, and remain the cell-culture system that most closely mimics the in vivo situation. Nevertheless, the model is limited, mainly because few sera give measurable level of intracellular HCVRNA. These considerations prompted us to study the relationship between host cell phenotype in culture, characteristics of viral isolates and serum infectivity. Our aim was then to establish a well-defined sera collection allowing studies of HCV infection in its natural host cell and evaluation of anti-HCV compounds. Methods: From kinetic experiments, we defined the optimal conditions to infect PHH. A standard test allowed classifying ~100 sera in 3 groups, based on their infectivity toward PHH. Sera were then carefully characterized (clinical profile of patient, viral load, genotype, and cytokine/growth factor content). Results: PHH support HCVser replication for at least two weeks with high level of RNA copies per cell and de novo virus production. We found that 12% of the sera tested are highly infectious (HI; more than 5x10 HCVRNA copies/mg of total RNA), 68% are poorly infectious (PI; less than 1.3x10 copies/mg) and 20% are intermediate (Inter). Infectivity toward PHH cannot be predicted from clinical characteristics of the serum donors, HCV viral load or genotype. The HI sera have a cytokine profile that clearly distinguishes them from other groups, with low levels of the majority of the 52 analytes tested, including cytokines involved in the regulation of immune responses and inflammatory reactions. Finally, the activity of antiviral compounds was evaluated against different clinical isolates. Conclusion: We defined optimal conditions to successfully infect PHH with HCVser and showed that this highly relevant model can be useful for understanding the mechanism of HCV infection, for selection of new HCV clones able to replicate in hepatoma cell lines and to determine the potency of new antiviral drugs toward various HCV strains.