Liver-Resident Memory CD8(+) T Cells: Possible Roles in Chronic HBV Infection

Achieving a functional cure for chronic hepatitis B virus (HBV) infection or complete elimination of HBV covalently closed circular DNA (cccDNA) has been challenging in the treatment of patients with chronic HBV infection. Although novel antivirals are being investigated, improving HBV-specific adaptive immune responses is also important for durable viral clearance. Tissue-resident memory CD8(+) T (T(RM)) cells were recently reported as a T-cell population that resides in peripheral tissues and does not recirculate. T(RM) cells have been studied in the livers of mice and humans. Liver T(RM) cells have distinct characteristics compared to T cells in peripheral blood or other tissues, which may be associated with the unique microenvironment of the liver. In this review, we describe the characteristics of liver T(RM) cells and their implications in chronic HBV infection. We emphasize that liver T(RM) cells can be an immunotherapeutic target for the treatment of chronic HBV infection.