BK polyomavirus large T antigen peptide–HLA complex (BKV LTAg-HLA) (BKV LTAg-HLA)

The BK polyomavirus large T antigen (LTAg) peptide–HLA complex is a molecular target consisting of viral peptides derived from the LTAg protein presented by Human Leukocyte Antigen (HLA) molecules on the surface of infected cells. LTAg is a multifunctional regulatory protein essential for BKV genome replication and cellular transformation, making it a primary target for the host's cellular immune response (UniProt P03071). In immunocompromised individuals, such as kidney or hematopoietic stem cell transplant recipients, BKV reactivation can lead to severe complications like BKV-associated nephropathy (BKVAN) or hemorrhagic cystitis (PubMed: 31534024). These peptide-HLA complexes are recognized by the T-cell receptors (TCRs) of cytotoxic CD8+ T cells, which then mediate the destruction of the infected host cells. Therapeutic strategies targeting these complexes involve the use of adoptive T-cell therapies, including virus-specific T cells (VSTs) and engineered TCR-T cells like Posoleucel, which aim to restore viral immunity (PubMed: 33852561). Monitoring BKV viral load in plasma and urine, along with the frequency of LTAg-specific T cells, serves as a critical biomarker for disease progression and treatment efficacy.

Other names

BKV LTAg-MHC complexBK virus large T antigen peptide-HLA complexBKV Large T-antigen-HLA complexBKV LTAg-HLA-A*02:01 complex

Recognition of the specific viral peptide presented within the HLA groove by the T-cell receptor (TCR) of cytotoxic T lymphocytes, which induces targeted cell lysis and cytokine production to inhibit viral spread.