Experimental Models: Cell Culture and Animal Models

Experimental models are indispensable tools for studying the biology of virus infection and for drug development. The narrow host range of hepatitis B virus (HBV), the lack of robust in vitro infection systems and the strong limitations imposed by the use of high primates have hindered progresses in drug development and understanding the complex network of virus-host interactions that are established in the course of HBV infection. Since mice and rats are not permissive for any of the known Hepadnaviridae, most research advances have been achieved by using transfection systems and outbred animal models based on HBV-related Hepadnaviridae and their relative hosts. The recent discovery of the cellular receptor mediating HBV entry is opening new possibilities to recapitulate the entire lifecycle in HBV-permissive hepatoma cell lines. This review focuses on summarizing recent advances obtained with well-established and more innovative experimental models, placing emphasis on the strength of new in vitro and in vivo infection systems that may serve as tools for elucidating still unknown steps of HBV biology, as well as for preclinical drug evaluation