Abrogation of hepatitis B virus infection in vivo by envelope protein derived entry inhibitors

Interference with HBV infection by externally applied fragments of viral surface proteins that interfere with receptor interaction or membrane fusion is a valuable approach for understanding key events of the hepadnaviral entry process. In addition this approach might also be important for the development of novel antiviral strategies, as has been shown for gp–41-derived T20-peptides in HIV-therapy. We have recently demonstrated that authentically myristoylated or otherwise acylated peptides encompassing the N-terminal 47 pre-S1 amino acids of the HBV L-protein block HBV infection of primary human and tupaia belangeri hepatocytes and HepaRG-cells with surprising efficacy, at already picomolar concentrations, probably by sustained inactivation of a receptor on hepatocytes. To test the potency of acylated HBV preS1 peptides to interfere with HBV infection also in vivo, we took advantage of the urokinase-type plasminogen activator (uPA) mouse model that supports the entire hepadnavirus replication cycle after liver repopulation with susceptible hepatocytes from humans or tupaia belangeri. We here report that treatment of mice with two different acylated preS1 peptides (HBVpreS/2–39myr (IC₅₀~300nM) and HBVpreS/2–48stearoyl (IC₅₀~250pM) completely inhibited the establishment of an HBV infection in vivo. HBsAg and viral DNA remained undetectable in serum of all mice (n=6) for at least five months after inoculation, while establishment of chronic productive infection with high viral titers was achieved in control mice treated with a myristoylated peptide derived from the Heron Hepatitis B Virus preS domain (HHBVpreS/2–44myr). The histochemical analysis of two treated mice revealed no HBV specific antigen staining 24 weeks after virus inoculation. Using 125I labeled HBVpreS/2–48myr we further investigated the organ distribution with respect to a specific targeting to the transplanted hepatocytes, as well as the peptide stability in serum. Our preclinical study proofs the principle that acylated preS-peptides are promising candidates for future clinical applications, e.g. prevention of HBV/HDV reinfection after liver transplantation, post exposure prophylaxis or horizontal transfer of HBV/HDV from an infected mother to her child. It remains an open question, if efficient entry inhibition in combination with established therapies that reduce the number of infected hepatocytes can improve the therapeutic outcome in chronically infected patients

Literatur: 1. Engelke, M., Mills, K., Seitz, S., Simon, P., Gripon, P., Schnölzer, M. Urban, S. Characterization of a Hepatitis B and Hepatitis Delta Virus receptor binding site in the preS-domain of the Hepatitis B Virus large surface protein. Hepatology, 2006 (in press) 2. Glebe, D., Urban, S., Knoop, E.V., Cag, N., Krass, P., Grün, S., Bulavaite, A., Sasnauskas, K., Gerlich, W.H. Mapping of the hepatitis B virus attachment site by infec-tion-inhibiting preS1 lipopeptides using primary Tupaia hepatocytes. Gastroenterology, 129, 234-245, 2005. 3. Gripon, P., Cannie, I., Urban, S. Efficient inhibition of hepatitis B virus infection by acy¬lated peptides derived from the large viral surface protein. J. Virol., 79 (3), 1613-1622, 2005. 4. Dandri, M. et al. Chronic infection with hepatitis B viruses and antiviral drug evaluation in uPA mice after liver repopulation with tupaia hepatocytes. J. Hepatol. 42, 54-60 (2005).

HBV receptor interaction - entry inhibition - uPA-RAG-2 mice