There is provided at least one isolated cell comprising at least one HBV epitope-reactive exogenous T cell receptor and/or fragment thereof, and methods for producing them. In particular, there is provided polynucleotides, constructs and vectors encoding at least one HBV epitope-reactive exogenous T cell receptor for use in the treatment of Hepatitis B Virus (HBV) and Hepatocellular Carcinoma (HCC). The invention further provides kits and methods of detection of HBV and HCC.
