Antiviral potency analysis and functional comparison of consensus interferon, interferon-α2a and pegylated interferon-α2b against hepatitis C virus infection

Background: Current treatments for chronic hepatitis C virus (HCV) employing pegylated interferon (PEG-IFN) plus ribavirin are successful in approximately 50% of patients. Consensus IFN (CIFN) is a recombinant type I IFN that has demonstrated efficacy where conventional therapy has failed. We evaluated the host cell antiviral response and anti-HCV actions induced by IFN-alpha 2a, PEG-IFN-alpha 2b or CIFN on cultured immortalized human hepatocytes, Huh7 human hepatoma cells and Huh7 cells that harboured genetically distinct HCV RNA replicons or were infected with HCV 2a. Methods: Cultured cells were treated with each IFN at relevant dosing based upon the pharmacological attainable in vivo serum maximum IFN concentrations. Gene expression and antiviral properties were measured using protein, RNA and virus quantification assays. Results: CIFN treatment maximally triggered Janus kinase signal transducer and activator of transcription signalling in association with enhanced IFN-stimulated gene (ISG) expression. Increased antiviral potency of CIFN was associated with enhancement of IFN-induced blockade upon viral protein synthesis, protection of the cellular IFN promoter stimulator-1 (IPS-1) protein from HCV proteolysis and reduced replication of an IFN-resistant HCV replicon variant. Microarray analyses revealed that CIFN treatment induced a distinct pattern of ISG expression in cultured hepatocytes compared with other IFNs. Conclusions: CIFN exhibits increased anti-HCV potency over IFN-alpha 2a and PEG-IFN through maximal and distinct induction of ISG expression and enhanced intracellular innate antiviral response, while protecting IPS-1 from HCV proteolysis. CIFN might offer a treatment regimen imparting translational control programmes and restoration of the retinoic acid-inducible gene-1/IPS-1 pathway and could be considered for previous treatment failures.