Functional Comparison of Interferon-α Subtypes Reveals Potent Hepatitis B Virus Suppression by a Concerted Action of Interferon-α and Interferon-γ Signaling

Background and Aims Interferon (IFN)-alpha, composed of numerous subtypes, plays a crucial role in immune defense. As the most studied subtype, IFN-alpha 2 has been used for treating chronic hepatitis B virus (HBV) infection, with advantages of finite treatment duration and sustained virologic response, but its efficacy remains relatively low. This study aimed to screen for IFN-alpha subtypes with the highest anti-HBV potency and to characterize mechanisms of IFN-alpha-mediated HBV restriction. Approach and Results Using cell culture-based HBV infection systems and a human-liver chimeric mouse model, IFN-alpha subtype-mediated antiviral response and signaling activation were comprehensively analyzed. IFN-alpha 14 was identified as the most effective subtype in suppression of HBV covalently closed circular DNA transcription and HBV e antigen/HBV surface antigen production, with median inhibitory concentration values approximately 100-fold lower than those of the conventional IFN-alpha 2. IFN-alpha 14 alone elicited IFN-alpha and IFN-gamma signaling crosstalk in a manner similar to the combined use of IFN-alpha 2 and IFN-gamma, inducing multiple potent antiviral effectors, which synergistically restricted HBV replication. Guanylate binding protein 5, one of the most differentially expressed genes between IFN-alpha 14-treated and IFN-alpha 2-treated liver cells, was identified as an HBV restriction factor. A strong IFN-alpha-IFN-alpha receptor subunit 1 interaction determines the anti-HBV activity of IFN-alpha. The in vivo anti-HBV activity of IFN-alpha 14 and treatment-related transcriptional patterns were further confirmed, and few adverse effects were observed. Conclusions A concerted IFN-alpha and IFN-gamma response in liver, which could be efficiently elicited by IFN-alpha subtype 14, is associated with potent HBV suppression. These data deepen the understanding of the divergent activities of IFN-alpha subtypes and the mechanism underlying the synergism between IFN-alpha and IFN-gamma signaling, with implications for improved IFN therapy and HBV curative strategies.