Hepatitis B Virus (HBV) infection results in the entry of viral genomic DNA into host liver cells. This viral relaxed circular DNA (rcDNA) is transported into the nucleus and converted into covalent closed-circular DNA (cccDNA), which serves as a template for viral transcription. Elimination of cccDNA is needed to cure HBV infection, which remains a major therapeutic challenge. A robust and sensitive method to measure cccDNA described here is useful to facilitate drug development and to monitor efficacy of therapy. A set of primers were designed in combination with sodium bisulfite treatment of viral DNA, allowing specific amplification of cccDNA without interfering amplification of rcDNA. This method can be used to further guide therapeutic development, and to provide a non-invasive alternative to monitoring of HBV-infected patients undergoing antiviral treatments.
