BK virus peptide-Human Leukocyte Antigen complex (BKV pHLA)

BK virus (BKV) is a polyomavirus that establishes lifelong latency in the renal tubular epithelial cells and urothelium of healthy individuals, but causes significant morbidity in immunocompromised patients, such as those undergoing kidney or hematopoietic stem cell transplantation [1]. Upon reactivation, the virus replicates, and its proteins—most notably the Large T-antigen (LTAg) and the major capsid protein VP1—are proteolytically processed into peptides and presented on the cell surface by Human Leukocyte Antigen (HLA) class I and II molecules [2]. These peptide-HLA (pHLA) complexes are the specific targets for the cellular immune system, particularly cytotoxic T lymphocytes (CTLs) that recognize the viral fragments and induce apoptosis in the infected cell [3]. In clinical settings where the endogenous immune response is insufficient, these complexes serve as the target for adoptive T-cell therapies, such as posoleucel, which consist of donor-derived T cells primed to recognize BKV-specific pHLA [4]. This therapeutic approach aims to clear the viral infection and prevent complications like BK virus-associated nephropathy (BKVAN) or hemorrhagic cystitis by leveraging the specificity of the T-cell receptor for the viral peptide-HLA complex [5]. The efficacy of these therapies depends on the precise matching of the T-cell receptor to the specific peptide-HLA combination presented by the patient's infected cells [6]. Monitoring of BKV viral load and the presence of BKV-specific T cells are essential for managing patient outcomes and determining the need for intervention [7].

Other names

BK virus-infected cellsBKV peptide-MHC complexBKV-HLA complexBKV antigen-presenting cellsBK polyomavirus peptide-HLA complex

T-cell receptor (TCR) mediated recognition and cytotoxic elimination of virally infected cells.