Established Hepatitis B Virus Infection Model In Vivo And In Vitro For Evaluation Of Anti-HBV Drug

Hepatitis B virus (HBV) is a small circular DNA virus, belonging to the hepadnavirus family. The virus attacks liver cells and can cause lifelong infection, scarring of the liver, liver failure, and death. Despite considerable advances in the understanding of the natural history of HBV infection, most of them,especially, the early steps,remain unclear as the lack of practicable primate little animal model in the past three decades.Chimpanzee was the first animal described for its susceptibility to HBV infection. However, chimpanzees are relatively rare and expensive, protected by law, no longer represent an appropriate model for HBV studies. The restriction of HBV infection to chimpanzee has increased demand for small animal models for studies HBV.A series of mouse models represent more accessible for HBV studies and evaluation of anti-HBV drug, but none of they could replace the chimpanzees. Transgenic mouse and hydrodynamic HBV mouse model are not susceptible to HBV infection, only be used for evaluation of antiviral drug. In addition, uPA-mouse transplanted human hepatocytes or tupaia hepatocytes can be used for HBV entry mechanism studies, but human hepatocytes are scare and difficulte to work, furthermore, tupaias may be better choice for HBV studies.Despite the narrow species specificity of hepadnaviruses, the susceptibility of tupaias for human HBV is approved. HBV infection in vitro, results in viral DNA and RNA synthesis in tupaia hepatocytes, and secretion hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) into culture medium. Moreover, tupaias can be infected with HBV in vivo, resulting in viral DNA replication and gene expression in tupaia livers, similar to acute self-limited hepatitis B in human, HBsAg is rapidly cleared from serum, followed by seroconversion to HBeAb and HBsAb.These reports strongly support tupaia as a valid model for experimental studies of HBV infection and evaluation of anti-HBV drug. However, evaluation of anti-HBV drug in vivo had been hampered by the lack of longitudinal analyses evaluating the clinical development and pathology of tupaias after HBV infection.HBV is one of the major threaten to human health and it was estimated that about more than 400 million people worldwide are chronically infected with HBV. Since currently available therapy strategies are restricted to anti-HBV replication by interferon- alpha (IFN-a) and nucleos(t)ide analogues, although, combination therapies, such as lamivudine combined with hepatitis B immunoglobulin or adefovir have been widely adopted for improve efficacy and avoid drug-resistant virus strains, but none of them could effectively eliminate HBV in patient, the number of HBV-infected people and HBV-related deaths continues to increase worldwide.Monoclonal antibodies against the S-domain were showed neutralized infectivity of HBV for primay human hepatocytes and primary tupaia hepatocytes cultures previously, and envelope protein-derived entry inhibitors resulted from the development of the HBV-susceptible cell line HepaRG. These inhibitors are acylated peptides derived from HBV preS1 domain could block virus attached to hepatocytes in vitro, especially, the preS1-derived peptides (HBVpreS/2-48myr) which can effectively block HBV infection at very low doses and bound strongly to hepatocytes but not to non hepatic cells. Thus, the N-terminal 47 amino acid residue of preS1 domain, are important in mediating attachment of HBV to hepatocytes.These dates indicat that myristoylated preS1-derived peptides (HBVpreS/2-48myr) are promising candidates for specific antiviral therapy against hepatitis B infections, leading to open a new perspectives for the future therapy of chronic hepatitisB and the emergence of resistant strains after antiviral treatment. But these preS1-derived peptides have not be examined in tupaias for evaluation of block virus infection in vivoTo validate whether L47 synthetic peptides derived from preS1 can impede HBV infection in tupaias, we verified its efficacy against virus attaching to tupaia hepatocytes in vitro model at first, and found its IC50 less than 2.5nM, then we used HBV-infected tupaias model for evaluation of L47 after longitudinal analyses of HBV pathogensis during the course of infection within 6 weeks. In this case, HBV caused tupaias hepatitis during the acute phase of infection, wherase HBV infection was constrained in tupaias treated with L47 at 0.08 mg/kg dose.