HMHB1
Description
The HMHB1 (histocompatibility minor HB-1) is a protein-coding gene located on chromosome 5.
HMHB1 is the precursor of the histocompatibility antigen HB-1. Minor histocompatibility antigens (mHags) are immunogenic peptides that, when complexed with MHC molecules, can trigger an immune response by specific T-cells. These peptides arise from polymorphic intracellular proteins processed through normal pathways. The binding of these peptides to MHC class I or II molecules and their presentation on the cell surface can stimulate T-cell responses, leading to graft rejection or graft-versus-host disease (GVHD) after hematopoietic stem cell transplantation from HLA-identical sibling donors. GVHD is a frequent complication following bone marrow transplantation (BMT), often due to mismatches in minor histocompatibility antigens in HLA-matched sibling marrow transplants. HB-1, presented on the cell surface by MHC class I HLA-B44, elicits donor-cytotoxic T lymphocyte (CTL) reactivity specifically in B-cell acute lymphoblastic leukemia (B-ALL) following HLA-identical allogenic bone marrow transplantation (BMT). It promotes cell recognition and lysis by CTLs. Importantly, HB-1's restricted expression in B-ALL cells, but not in normal tissues, allows for specific CTL reactivity against B-ALL without the risk of triggering GVHD.
HMHB1 is also known as HB-1, HB-1Y, HLA-HB1.
