Hepatitis B virus (HBV) is a major healthy problem worldwide. Because of the narrow host range of HBV, relative research was hampered by lacking of an appropriate animal model. The natural history of woodchuck hepatitis virus (WHV) infection in woodchuck is highly similar to that of HBV infection in human. Therefore this animal may be an valuable species for establishing an in vivo and in vitro HBV infection model to evaluate HBV DNA vaccines and anti-HBV drugs. Sodium taurocholate cotransporting polypeptide (NTCP) is the functional receptor for HBV and hepatitis D virus (HDV) infection. Considering that HBV cannot successfully infect woodchuck cells possibly due to the difference of the functional domain between woodchuck NTCP (wNTCP) and human NTCP (hNTCP), therefore, we tried to make woodchuck hepatocytes susceptible to HBV infection by replacing wNTCP with hNTCP .
The sequences alignment showed the functional domain of hNTCP related to HBV binding and entry process was different from wNTCP. In this study, hNTCP was introduced into the woodchuck hepatocytes by different approaches including transduction of vLentivirus-hNTCP in woodchuck hepatocytes, transfection of plentivirus-hNTCP-eGFP plasmids in woodchuck hepatocytes, as well as transduction of vAdenovirus-hNTCP-eGFP in woodchuck hepatocytes, in an attempt to make the woodchuck hepatocytes susceptible to HBV. After check the expression of hNTCP by immunofluorescence, the hNTCP-expressed woodchuck hepatocytes were then used to test its susceptibility to HBV infection, which was evaluated by secreted HBeAg in the supernatants. In order to determine whether these hNTCP-expressed hepatocytes could be infected by HDV, the established vAdenovirus-hNTCP-eGFP transduced woodchuck hepatocytes were subsequently subjected to HDV infection, and HDV viral genome was quantified by real-time PCR.
hNTCP was successfully introduced to the woodchuck hepatocytes by using above three different methods. However, hNTCP-expressed woodchuck hepatocytes could not be infected by HBV. Nevertheless, we found that woodchuck hepatocytes containing hNTCP were sensitive to HDV infection.
This study indicating that there exist some other key factors mediate the HBV infection at early stage which have strict species specificity, and hNTCP is not the only determinant needed for HBV successful infection.