Cytomegalovirus Immediate-early protein 1 peptide–MHC class I complex (IE1-pMHC)

The Cytomegalovirus Immediate-early protein 1 (IE1) peptide–MHC class I complex is a critical molecular target for the cellular immune response against Human Cytomegalovirus (HCMV) (UniProt P06473). IE1, encoded by the UL123 gene, is one of the first proteins expressed upon viral entry and plays a vital role in initiating viral replication and modulating the host's innate immune response by antagonizing interferon signaling (PMID: 15919923). During infection, IE1 is processed by the proteasome into short peptides that are subsequently loaded onto MHC class I molecules and presented on the surface of infected cells (PMID: 25653437). These peptide-MHC complexes are specifically recognized by the T-cell receptors (TCRs) of CD8+ cytotoxic T-lymphocytes, which trigger the destruction of the infected cell. In therapeutic contexts, these complexes serve as the primary docking site for adoptive T-cell therapies and TCR-engineered T cells designed to restore or enhance CMV-specific immunity in immunocompromised patients, such as those undergoing hematopoietic stem cell or solid organ transplantation (PMID: 30635473). Targeting these complexes is essential for controlling viral reactivation and preventing CMV-associated morbidity and mortality. Because IE1 is expressed very early in the viral life cycle, it is an ideal target for early detection and elimination of infected cells before the production of new virions.

Other names

HCMV IE1-pMHCUL123 peptide-HLA complexIE1-MHC I complexCytomegalovirus IE1-MHC class I complexIE1-HLA-A*02:01 complex

Recognition by specific T-cell receptors (TCRs) on CD8+ cytotoxic T-lymphocytes, leading to the release of cytotoxic granules (perforin and granzymes) and subsequent apoptosis of the CMV-infected cell (PMID: 25653437).