BK polyomavirus small T antigen-derived peptide-major histocompatibility complex (BKV sT-pMHC)

BK polyomavirus (BKV) small T antigen-derived peptide-major histocompatibility complex (pMHC) is a cell-surface target consisting of viral peptide fragments presented by host MHC Class I molecules. The small T antigen (sT) is an early viral protein essential for BKV DNA replication and the modulation of host cell cycles through the inhibition of protein phosphatase 2A (PP2A) (Source: PubMed 26136448). During active infection or reactivation, sT is processed by the host's proteasome into peptides that are loaded onto MHC molecules for presentation to the immune system (Source: PubMed 28633860). These pMHC complexes serve as the specific recognition site for CD8+ cytotoxic T lymphocytes, which are responsible for identifying and killing BKV-infected cells. In immunocompromised patients, such as those undergoing kidney transplantation, the failure of the immune system to recognize these targets leads to BKV-associated nephropathy (BKVAN) or hemorrhagic cystitis. Therapeutic strategies like adoptive virus-specific T-cell (VST) therapies, including Posoleucel, are designed to target these complexes to restore viral control (Source: Allovir). The efficacy of such treatments depends on the presence of specific HLA alleles and the density of the pMHC complexes on the surface of infected tissues.

Other names

BKV sT-HLA complexBK virus small T antigen-MHC complexBKV sAg-pMHCBK polyomavirus sT-HLA-A*02:01 complex

Recognition of viral peptides presented on MHC molecules by T-cell receptors (TCRs), leading to targeted lysis of infected cells.