Liver-specific expression of interferon γ following adenoviral gene transfer controls hepatitis B virus replication in mice

Abstract

Interferons control viral replication and the growth of some malignant tumors. Since systemic application may cause severe adverse effects, tissue-specific expression is an attractive alternative. Liver-directed interferon gene therapy offers promising applications such as chronic viral hepatitis B or C or hepatocellular carcinoma and thus needs testing in vivo in suitable animal models. We therefore used the Tet-On system to regulate gene expression in adenoviral vectors, and studied the effect of liver-specific and regulated interferon g expression in a mouse model of chronic hepatitis B virus (HBV) infection. In a first generation adenoviral vector, genes encoding for firefly luciferase and interferons a, b or g, respectively, were coexpressed under control of the bidirectional tetracycline-regulated promoter P tet bi. Liverspecific promoters driving expression of the reverse tetracycline controlled transactivator ensured local expression in the livers of HBV transgenic mice. Following gene transfer, we demonstrated low background, tight regulation and a 1000-fold induction of gene expression by doxycycline. Both genes within the bidirectional transcription unit were expressed simultaneously, and in a liver-specific fashion in cell culture and in living mice. Doxycycline-dependent interferon g expression effectively controlled HBV replication in mice, but did not eliminate HBV transcripts. This system will help to study the effects of local cytokine expression in mouse disease models in detail. Gene Therapy (2005) 12, 668-677.

Elimination of Immunodominant Epitopes from Multispecific DNA-Based Vaccines Allows Induction of CD8 T Cells That Have a Striking Antiviral Potential

“…7B). pCI/C vaccination had no significant effect on viral RNA levels in the liver of tg animals (data not shown), confirming previously published data from an adenovirus-based vaccination study in another HBV tg mouse model (46). The HBcAg-specific, antiviral immune response in the liver of 1.4HBV-S mut tg mice did not elicit a rise in serum transaminase levels (Fig.…”

Liver-Directed Gamma Interferon Gene Delivery in Chronic Hepatitis C

“…For generation of the recombinant adenoviral vector, human IFN-␥ cDNA was introduced into the E1 region of a first generation, E1/E3-deleted adenovirus type 5 vector under control of a transthyretin promoter using the AdEasy system (13). Ad vectors were grown, concentrated, and purified as described previously (6). Intrahepatic expression of murine IFN-␥ by rAd vectors has previously been shown to control HBV replication in mice (6).…”

“…Ad vectors were grown, concentrated, and purified as described previously (6). Intrahepatic expression of murine IFN-␥ by rAd vectors has previously been shown to control HBV replication in mice (6).…”

Induction of Antiviral Cytidine Deaminases Does Not Explain the Inhibition of Hepatitis B Virus Replication by Interferons

“…Inhibition of HBV replication by IFNs is independent of antiviral cytidine deaminases. IFN-␥ and IFN-␣ are demonstrated inhibitors of HBV replication both in vitro and in vivo (9,10,15,22,35,40,42,54), and both cytokines induce the expression of cytidine deaminases capable of blocking this virus (Fig. 3).…”