BK polyomavirus Large T antigen (BKPyV LTA)

The BK polyomavirus Large T antigen (LTA) is a multifunctional regulatory protein essential for the viral life cycle. It acts as a DNA helicase and a transcription factor, driving the replication of the viral genome by recruiting host cell machinery and binding to the viral origin of replication. LTA is notorious for its ability to bind and inactivate tumor suppressor proteins, such as p53 and the retinoblastoma (pRb) family, effectively forcing the host cell into the S-phase of the cell cycle to facilitate viral synthesis. In immunocompromised individuals, particularly kidney transplant recipients, the reactivation of BK virus and the subsequent expression of LTA lead to BK virus-associated nephropathy (BKVAN), a leading cause of graft loss. While there are no currently FDA-approved drugs specifically targeting LTA, it is a primary focus for novel immunotherapies, including virus-specific T-cell therapies like Posoleucel, and remains a critical diagnostic marker through immunohistochemical staining in renal biopsies.

Other names

Large T-antigenBKV LTABKPyV Large T-antigenLTagBK virus T-antigen

Targeting of viral DNA replication through helicase inhibition, stimulation of cytotoxic T-lymphocyte response against LTA-expressing cells, and inhibition of viral early gene expression.