Cytomegalovirus immediate-early 1-derived peptide–major histocompatibility complex class I complex (CMV IE1–pMHC I)

The Cytomegalovirus (CMV) immediate-early 1 (IE1)-derived peptide–major histocompatibility complex (MHC) class I complex is a molecular assembly presented on the surface of cells infected with human cytomegalovirus (HCMV). The IE1 protein (encoded by the UL123 gene) is one of the first viral proteins expressed during the lytic cycle and is a primary target for the host's cellular immune response. Specific peptides derived from IE1, such as the HLA-A*02:01-restricted VLEETSVML epitope, are loaded onto MHC class I molecules in the endoplasmic reticulum and transported to the cell surface. These complexes serve as critical ligands for the T-cell receptors (TCRs) of CD8+ cytotoxic T lymphocytes, which monitor and eliminate infected cells. In therapeutic contexts, these complexes are targeted by adoptive T-cell therapies, TCR-engineered T cells (TCR-T), and peptide-based vaccines, particularly in immunocompromised individuals like hematopoietic stem cell or solid organ transplant recipients who are at high risk for CMV-related morbidity. The specificity of the interaction between the TCR and the IE1-pMHC complex is a cornerstone of precision immunotherapy against CMV.

Other names

CMV IE1 peptide-HLA complexHuman cytomegalovirus UL123 peptide-MHC class I complexHCMV IE1-pMHCIE1-derived peptide-MHC class I complex

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