Replication-driven HBV cccDNA loss in chimeric mice with humanized livers

Hepatitis B virus (HBV) infection is largely noncytopathic and requires the establishment of covalently closed circular DNA (cccDNA), which is considered stable in the nuclei of infected cells. Although challenging, approaches to directly target cccDNA molecules or kill infected cells are recommended to eliminate cccDNA. Herein, cccDNA levels were investigated in HBV-infected chimeric mice with humanized livers. HBV-infected cells support robust replication, progressively retain viral products, and head for cytopathic destruction and cccDNA loss. It is difficult for infected cells to retain cccDNA and remain noncytopathic. Replication-driven cccDNA loss is observed at both phases of spread of and persistent infection. The cccDNA replenishment is required to compensate for cccDNA loss. Blocking cccDNA replenishment pathways reduces cccDNA levels by >100-fold. These results prove an unconventional cccDNA elimination strategy that does not directly target cccDNA but aims to transform spontaneous cccDNA loss into progressive cccDNA elimination by blocking cccDNA replenishment.