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

The BK polyomavirus large T antigen (LTAg)-derived peptide–HLA complex is a specific molecular target presented on the surface of cells infected with the BK polyomavirus (BKV). BKV is a double-stranded DNA virus that remains latent in the renal tubular and urothelial cells of most healthy individuals but can reactivate in immunocompromised patients, such as kidney or hematopoietic stem cell transplant recipients [1]. The large T antigen is a multifunctional regulatory protein essential for viral DNA replication and is the primary target for the host's cellular immune response [2]. Peptides derived from LTAg are processed and presented by Human Leukocyte Antigen (HLA) Class I molecules, such as HLA-A*02:01, to be recognized by the T-cell receptors (TCRs) of CD8+ cytotoxic T lymphocytes [3]. Therapeutic strategies targeting these complexes include the development of adoptive T-cell therapies, such as virus-specific T cells (VSTs) like posoleucel, or TCR-engineered T cells, which aim to restore or enhance the immune system's ability to clear the virus [4]. Monitoring these complexes and the corresponding T-cell response is vital for managing transplant recipients at risk of BKV-associated nephropathy (BKVAN) or hemorrhagic cystitis [5]. Citations: [1] Hirsch HH, Randhawa P. Am J Transplant. 2019. [2] Abend JR, et al. Virology. 2009. [3] Leboeuf C, et al. Am J Transplant. 2017. [4] AlloVir. Posoleucel (ALVR106) Development. 2023. [5] Blyth E, et al. Blood. 2013.

Other names

BKV LTAg-MHC complexBK virus large T antigen peptide-HLA complexBKV LTAg pMHCBK polyomavirus large tumor antigen-derived peptide–HLA complex

T-cell receptor (TCR) mediated recognition of the peptide-HLA complex, triggering cytotoxic T-lymphocyte (CTL) activation and subsequent apoptosis of the infected host cell.