Histocompatibility minor antigen HB-1 (HB-1)

Histocompatibility minor antigen HB-1 is a peptide derived from the HMHB1 gene, presented on the cell surface by MHC class I HLA-B44. It is a minor histocompatibility antigen, which can induce specific cytotoxic T lymphocyte (CTL) activity, especially in the context of hematopoietic stem cell transplantation from HLA-identical donors. HB-1 is highly and restrictively expressed in B cell acute lymphoblastic leukemia (B-ALL) cells and Epstein-Barr virus-transformed B cells but not in the majority of normal tissues. The HB-1 peptide can trigger robust CTL responses that specifically target malignant B cells, offering potential for graft-versus-leukemia immunotherapy with decreased risk of graft-versus-host disease, as normal healthy tissues generally lack substantial HB-1 expression. HB-1 is produced from a rare transcript, translated from a non-canonical start codon (CUG), giving rise to a 41-amino acid protein from which the immunogenic peptide is derived. Polymorphisms in the HB-1 peptide affect its recognition by T lymphocytes and influence the graft-versus-leukemia effect and susceptibility to transplantation complications.

Other names

HMHB1minor histocompatibility antigen HB-1mHag HB-1

Peptide-specific CTL targeting (cellular immunotherapy aims to elicit CTL that recognize HB-1 peptide presented by MHC class I HLA-B44)