The present invention relates to peptides and their ability to identify and bind to T cells specific for HBV-infected hepatocytes. In a first aspect of the invention, there is provided a peptide comprising an amino acid sequence selected from the group consisting of STLPETAVVRR (SEQ ID NO: 21), STLPETAVVR (SEQ ID NO: 22), STLPETTVVRR (SEQ ID NO: 23), STLPETTVTRR (SEQ ID NO: 24), STPPETTVVRR (SEQ ID NO: 25), STLPETTVVGR (SEQ ID NO: 26) and STIPETTVVRR (SEQ ID NO: 27), wherein the peptide is derived from Hepatitis B virus core169 and is capable of binding HLA-A*1101 and when bound to HLA-A*1101 is capable of identifying T cells specific for Hepatitis B virus. In a second aspect of the invention, there is provided a T cell expressing a T cell receptor (TCR) molecule, wherein the TCR molecule comprises an amino acid sequence selected from the group consisting of CASGDSNSPLHF (SEQ ID NO: 17), CASSGGQIVYEQYF (SEQ ID NO: 18), CSARGGRGGDYTF (SEQ ID NO: 19) and CASSQDWTEAFF (SEQ ID NO: 20), and wherein the TCR molecule is able to bind to a peptide according to the first aspect of the invention.