Hepatitis B Virus

Yi Ni, Stephan Urban

Investigations of virus-host interactions rely on suitable in vitro cell culture systems that efficiently support virus infection. Such systems should ideally provide conditions that resemble those of natural host cells, e.g., the cell-type specific signaling and metabolic pathways. For HBV infection, primary human hepatocytes (PHHs) are the most faithful system fulfilling these requirements but access to these cells is limited. Moreover, the reproducibility of experimental results depends on many factors including the preparation method or variability of the donors. The human liver cell line HepaRG, after differentiation, resembles PHHs with respect to many hepatocyte-specific markers including the expression of cytochrome P450 enzymes, liver-specific transcription factors, and transporter proteins like the HBV-specific receptor, sodium taurocholate co-transporting polypeptide (NTCP). HepaRG cells have also been shown to express key molecules of the innate immune system. So far, the HepaRG cell line is the only one allowing both studies on HBV/HDV infection and liver-specific drug toxicity and metabolism. The relative low susceptibility of HepaRG cells when compared with PHHs depends on various factors and can partially be overcome by constitutive expression of the receptor NTCP, allowing infection without full differentiation. Ectopic NTCP expression does not interfere with the ability of cell differentiation induced by DMSO. Here, we describe in detail how to technically perform HBV infection in vitro with these cells. The methods can be used to explore the mechanism of HBV infection and to build an antiviral screening platform suitable for evaluation of drug efficacy in cells that are metabolically close to primary human hepatocytes.