Hepatitis B virus surface antigen S20-28 peptide presented by human leukocyte antigen class I histocompatibility antigen, A-2 alpha chain (HBsAg S20-28–HLA-A*02:01)

The "Hepatitis B surface antigen S20-28 peptide presented on HLA-A*02:01" refers to a specific 9-mer epitope (amino acids 20–28 of the hepatitis B virus surface antigen, commonly referred to as HBsAg) bound within the peptide-binding groove of the human major histocompatibility complex class I allele HLA-A*02:01. This peptide–MHC complex is displayed on the surface of hepatocytes infected by hepatitis B virus, where it is recognized by cytotoxic CD8+ T cells as part of the adaptive immune response. Effective T cell recognition of this complex is a central mode of viral clearance and underpins strategies for developing T cell–based immunotherapies and vaccines. This target is being investigated for potential immune-redirecting biologics—such as ImmTAV molecules—that can selectively eliminate infected cells by recognizing the HLA-A*02:01–peptide complex[7]. Its clinical utility is restricted by patient HLA type and immunodominance characteristics of the viral peptide.

Other names

Hepatitis B surface antigen S20-28 epitope–HLA-A*02:01 complexHBsAg S(20-28)/HLA-A*02:01HLA-A*02:01-restricted HBV Env-derived peptide[7]HBV S20-28 epitope–HLA-A*02:01

Antigen-specific CD8+ T cell activation via recognition of the peptide–MHC complex on infected cells Potential recruitment of immune therapeutics (e.g., TCR-mimetic proteins or bispecifics) that target the peptide–MHC complex for selective killing[7]