Cytomegalovirus-derived peptide–Human Leukocyte Antigen complex (CMV-pMHC) (CMV-pMHC)

The Cytomegalovirus-derived peptide–Human Leukocyte Antigen (CMV-pMHC) complex is a critical immunological target formed when peptides from the human cytomegalovirus (HCMV), such as those from the pp65 (UL83) or IE1 proteins, are processed and presented on the cell surface by HLA class I molecules. This complex is specifically recognized by the T-cell receptors (TCRs) of CD8+ cytotoxic T lymphocytes, which is the primary mechanism for controlling CMV infection in healthy individuals. In immunocompromised patients, such as those undergoing hematopoietic stem cell or solid organ transplantation, the absence of a robust T-cell response against these complexes can lead to viral reactivation, causing significant morbidity and mortality. Therapeutic interventions targeting the CMV-pMHC complex include the adoptive transfer of CMV-specific T cells, TCR-engineered T cells, and the development of TCR-like antibodies or bispecific T-cell engagers that can specifically bind the complex and redirect immune effector cells to kill infected targets. These therapies aim to restore or bypass the host's impaired immune surveillance to eliminate the viral reservoir. However, the high degree of HLA polymorphism restricts specific therapies to certain patient populations, and the risk of off-target cross-reactivity with similar self-peptides remains a significant safety concern. Additionally, CMV has evolved mechanisms to downregulate HLA expression, which can hinder the efficacy of these targeted approaches.

Other names

CMV-HLA complexCMV peptide-MHC complexHCMV-pMHCCMV-pHLA complexCytomegalovirus peptide-major histocompatibility complex

Recognition by T-cell receptors (TCRs) or TCR-like antibodies, leading to the activation of cytotoxic T lymphocytes (CTLs) and subsequent lysis of CMV-infected cells.