Hepatitis B virus surface antigen peptide-Major Histocompatibility Complex (HBsAg-MHC) (HBsAg-MHC)

The Hepatitis B virus surface antigen (HBsAg) peptide-Major Histocompatibility Complex (MHC) is a molecular assembly found on the surface of HBV-infected hepatocytes and HBV-related tumor cells (PubMed, PMID: 34256352). It consists of a short peptide fragment derived from the HBsAg protein nested within the binding groove of an MHC class I molecule, typically HLA-A*02:01 in clinical applications (SCG Cell Therapy, 2023). This complex serves as a critical signal for the immune system, specifically allowing CD8+ cytotoxic T cells to identify and eliminate cells harboring the virus or viral integration (Frontiers in Immunology, 2022). In the context of chronic infection, natural T-cell responses are often exhausted or insufficient, making this complex a primary target for adoptive cell therapies such as TCR-engineered T cells (TCR-T). By targeting this specific peptide-MHC assembly, therapeutic agents like SCG101 can selectively direct a potent immune response against infected or malignant cells while sparing healthy tissue that does not express the viral antigen (ClinicalTrials.gov, NCT05417932). Clinical development focusing on this target aims to achieve functional cures for chronic hepatitis B and provide new treatment options for HBV-associated hepatocellular carcinoma.

Other names

HBsAg-HLA complexHBV surface antigen-MHC complexHBsAg peptide-HLA-A*02:01 complexHBsAg-pMHC

Therapeutic T-cell receptors (TCRs) or TCR-like antibodies recognize the specific viral peptide sequence presented by the MHC molecule, leading to the activation of cytotoxic T cells and subsequent lysis of the target cell (PubMed, PMID: 34256352).