Sodium-dependent taurocholic cotransporting polypeptide: a candidate receptor for human hepatitis B virus

The DHBV model seemed particularly suitable, because duck primary hepatocytes (dPHCs) are easy to prepare and a large fraction can be productively infected in culture with DHBV. [...]virus-binding experiments demonstrated high-affinity binding sites or receptors on duck hepatocytes and, importantly, showed that these binding sites exhibit species- and tissue-specificity, consistent with the restricted host range and tissue tropism characteristic of the Hepadnaviridae. 1 2 In the meantime, Tupaias (treeshrews), belonging to the family Tupaiidae, and not considered primates, were shown to be susceptible to HBV infection. 3 Tupaia primary hepatocyte cultures (tPHCs) are also permissive for HBV and HDV infection, and provided a new tool in the search for the HBV receptor. 4 Finally, lentiviruses pseudotyped with HBV envelope proteins were shown to infect human primary hepatocytes (hPHCs). [...]as measured by binding of the wild-type peptide, NTCP decreased with time in hepatocyte cultures, suggesting that expression of this receptor candidate may be controlled by liver-specific transcription, which declined during in vitro maintenance of hepatocytes. [...]Yan et al demonstrated that a peptide spanning amino acids 157-165 in NTCP carries determinants for species specificity, a hallmark of hepadnaviruses ( figure 1 ). [...]the identification of NTCP as a candidate HBV receptor may provide a new target for antiviral therapy, a significant advance, considering that the polymerase is so far the only target for clinically effective drugs.