BK polyomavirus peptide–Major Histocompatibility Complex (BKV pMHC)

BK polyomavirus (BKV) peptide–Major Histocompatibility Complex (MHC) complexes are molecular assemblies presented on the surface of cells infected with BKV. These complexes consist of short viral protein fragments, typically derived from the Large T-antigen or VP1 capsid protein, bound within the groove of MHC (HLA in humans) molecules. They serve as the primary recognition signal for the host's cellular immune system, specifically for BKV-specific CD8+ and CD4+ T cells. In immunocompromised patients, such as kidney or hematopoietic stem cell transplant recipients, BKV can reactivate and cause severe complications like BKV-associated nephropathy or hemorrhagic cystitis. Therapeutic strategies targeting these complexes involve adoptive T-cell therapies, such as posoleucel, which utilize donor-derived T cells engineered or selected to recognize these specific pMHC targets to restore viral control and clear infected cells. While promising, these therapies face challenges including the risk of graft-versus-host disease and the potential for viral immune escape through mutations in the presented peptides.

Other names

BKPyV peptide-HLA complexBKV pMHCBK virus antigen-MHC complexBKV peptide-MHCBK polyomavirus peptide-HLA complex

Recognition of the peptide-MHC complex by the T-cell receptor (TCR) of virus-specific T cells, triggering cytotoxic activity and cytokine release to eliminate infected cells.