T-cell receptor on HBV-specific CD4+ T cells (TCR)

The T-cell receptor (TCR) on HBV-specific CD4+ T cells is a specialized protein complex on the surface of helper T lymphocytes that recognizes specific fragments of the Hepatitis B virus (HBV) (Altimmune, 2024). These TCRs specifically bind to HBV-derived peptides, such as the nine synthetic peptides contained in the HepTcell immunotherapeutic, when they are presented by Human Leukocyte Antigen (HLA) class II molecules on antigen-presenting cells (ClinicalTrials.gov, NCT04620330). In patients with chronic HBV infection, these T cells are typically dysfunctional or exhausted, failing to control viral replication. By engaging these TCRs, HepTcell aims to break immune tolerance and stimulate the proliferation of functional CD4+ T cells that can coordinate a broader immune attack against the virus (Gaggar et al., 2023). Activated CD4+ T cells provide critical help to CD8+ cytotoxic T cells and B cells, which are necessary for the clearance of infected hepatocytes and the production of anti-HBV antibodies. This target is central to the development of therapeutic vaccines intended to achieve a functional cure for chronic HBV by restoring the host's endogenous immune response.

Other names

HBV-specific CD4+ T-cell receptorHepTcell-targeted TCRHepatitis B virus-specific T-cell receptorCD4+ T-cell receptor recognizing HBV peptide-HLA class II complexes

HepTcell acts as an immunotherapeutic agonist by providing a pool of nine synthetic HBV-derived peptides that are processed and presented by HLA class II molecules; these complexes bind to and activate specific T-cell receptors on CD4+ T cells to restore and expand the anti-viral immune response.