Cytomegalovirus pp65 and IE1 peptides presented on HLA class I (CMV pp65/IE1-HLA)

Cytomegalovirus (CMV) pp65 and IE1 peptides presented on patient-specific HLA class I molecules are primary targets for the cellular immune response against Human Cytomegalovirus (HCMV) (Arvin et al., 2004). HCMV is a beta-herpesvirus that causes significant morbidity in immunocompromised hosts, such as transplant recipients, where reactivation can lead to organ failure (PubMed: 25605961). The pp65 protein (UL83) is a major structural component of the viral tegument and serves as the immunodominant target for CD8+ T cells, while the IE1 protein (UL123) is produced during the immediate-early phase of viral replication (UniProt: P06725, P13202). These proteins are processed into short peptides and presented by patient-specific HLA class I molecules on the surface of infected cells to be recognized by specific T-cell receptors (TCRs). Therapeutic approaches targeting this complex include adoptive T-cell therapy using donor-derived or off-the-shelf CMV-specific T cells, such as Posoleucel (AlloVir, 2023). Additionally, viral vector vaccines like Triplex are designed to prime the immune system against these specific antigens to prevent CMV reactivation (City of Hope, 2022). This target is highly specific to virally infected cells, and monitoring the frequency of T cells specific to these complexes serves as a biomarker for immune reconstitution.

Other names

CMV pp65/IE1-MHC complexUL83/UL123-HLA complexCytomegalovirus antigen-HLA complexCMV-specific peptide-MHC class I complex

Recognition by T-cell receptors (TCRs) on CD8+ cytotoxic T-lymphocytes, leading to the targeted lysis of CMV-infected cells.