IL2-inducible T-cell Kinase is Required for HBV-induced Type T Interferon Expression and Antiviral Response

BACKGROUND AND AIMS: Hepatitis B is a vaccine-preventable liver infection caused by the hepatitis B virus (HBV), and is seen as a serious global health problem. HBV infection induces the expression of type I interferon (IFN), including IFN-α and IFN-β, which have anti-HBV activities, and have been used for HBV treatment. IL2-inducible T-cell kinase (ITK) is a tyrosine kinase, which regulates T-cell differentiation and activation, while its precise effects on type I IFN production during HBV infection remain unknown. METHODS: We monitored the ITK expression in peripheral blood mononuclear cells (PBMCs) from healthy donors and patients with acute and chronic HBV infection. We used ITK inhibitor ibrutinib to treat hepatocytes and evaluated the type I IFN expression after HBV infection. We also administrated ibrutinib to mice and evaluated its effect on HBV infection in vivo. We generated ITK, suppressor of cytokine signaling 1 (SOCS1) knockout and ITK/SOCS1 double knockout cells using CRISPR, and monitored the HBV-induced type I IFN production. RESULTS: ITK and type I IFN were upregulated in patients with acute HBV infection. Inhibition of ITK by ibrutinib suppressed HBV-induced expression of type I IFN mRNA in mice. ITK knockout cells had decreased IRF3 activation but promoted the expression of SOCS1. ITK negatively regulated SOSC1 expression. The down regulation of type I IFN in ITK knockout cells after HBV stimulation was abolished in the absence of SOCS1. CONCLUSIONS: ITK regulated HBV-induced expression of type I IFN mRNA by modulating SOCS1.