Cytomegalovirus phosphoprotein 65 peptide epitope presented by HLA class I (CMV pp65/HLA-I complex)

The CMV pp65 peptide epitope presented by HLA class I is a molecular complex formed by the association of a peptide derived from the 65 kDa phosphoprotein (pp65, also known as UL83) of Human Cytomegalovirus (HCMV) with a Human Leukocyte Antigen (HLA) class I molecule (NIH, 2022). This complex is the primary target for the host's cellular immune response, particularly CD8+ cytotoxic T lymphocytes (CTLs), which recognize the epitope via their T-cell receptors (TCRs) (Frontiers, 2022). In healthy individuals, this interaction maintains viral latency; however, in immunocompromised patients, such as those undergoing hematopoietic stem cell or solid organ transplantation, the absence of effective pp65-specific T cells leads to viral reactivation and severe disease (NIH, 2022). Therapeutic interventions targeting this complex include adoptive transfer of virus-specific T cells (VSTs), TCR-engineered T cells, and peptide-based vaccines designed to restore or enhance the immune response (MDPI, 2021). Additionally, because pp65 is expressed in certain malignancies like glioblastoma, this complex is being explored as a target for cancer immunotherapy (NIH, 2025). These strategies aim to selectively eliminate CMV-infected or pp65-expressing cells while minimizing damage to healthy tissues.

Other names

CMV pp65 pMHCUL83 peptide-HLA complexCMV pp65 epitopeHLA-restricted CMV pp65 peptideNLVPMVATV/HLA-A*02:01 complex

Recognition of the peptide-MHC complex by T-cell receptors (TCRs) or TCR-like antibodies, which triggers the activation and expansion of cytotoxic CD8+ T cells, leading to the targeted destruction of CMV-infected or pp65-expressing cells through the release of perforin and granzymes.