Cytomegalovirus immediate-early 1 (CMV IE1) antigen-derived peptides presented on MHC class I (CMV IE1-MHC I)

The Cytomegalovirus (CMV) immediate-early 1 (IE1) protein, also known as UL123, is one of the first viral proteins expressed upon infection or reactivation from latency (UniProt: P06473). Peptides derived from IE1 are processed by the proteasome and loaded onto Major Histocompatibility Complex (MHC) class I molecules for presentation on the cell surface. These IE1-MHC I complexes are crucial for the recognition of infected cells by CD8+ cytotoxic T lymphocytes (CTLs), which play a dominant role in controlling CMV infection (PMID: 15919923). Because IE1 is expressed so early, it is an ideal target for the immune system to intercept viral replication before the assembly of new virions. In therapeutic contexts, these complexes are targeted by adoptive T-cell therapies, such as posoleucel, and various vaccine candidates like mRNA-1647 to prevent or treat CMV disease in immunocompromised patients (NCT04356612, NCT04693637). The specificity of the interaction depends on the patient's HLA type, with epitopes like VLEETSVML being commonly targeted in HLA-A*02:01 positive individuals.

Other names

HCMV IE1-HLA complexUL123 peptide-MHC complexCMV IE1 epitopeIE1-derived MHC I ligandVLEETSVML-HLA-A*02:01 complex

T-cell receptor (TCR) binding and activation of cytotoxic T lymphocytes