Cytomegalovirus immediate-early 1 protein-derived peptide-MHC class I complex (CMV IE1-pMHC-I)

The Cytomegalovirus immediate-early 1 (IE1) protein-derived peptide-MHC class I complex is a critical immunological target for the control of Human Cytomegalovirus (HCMV) infection. The IE1 protein, encoded by the UL123 gene, is one of the first viral proteins expressed upon infection or reactivation from latency, playing a vital role in transactivating viral gene expression and modulating the host's innate immune response (UniProt: P06473). Peptides derived from IE1 are processed via the endogenous pathway and presented on the cell surface by MHC class I molecules, where they serve as primary targets for recognition by CD8+ cytotoxic T lymphocytes (CTLs). Because IE1 is expressed so early in the viral life cycle, IE1-specific T cells can identify and eliminate infected cells before the production of mature virions, making this complex a high-priority target for immunotherapies (PubMed: 11836371). Therapeutic strategies targeting this complex include the infusion of ex vivo expanded CMV-specific T cells (VSTs) and the development of vaccines, such as Triplex, which aim to bolster the immune response in immunocompromised patients, particularly hematopoietic stem cell and solid organ transplant recipients (ClinicalTrials.gov: NCT02506933).

Other names

CMV IE1 peptide-HLA complexIE1-derived epitopesUL123-derived peptides presented on MHC-ICMV IE1 antigenIE1-specific pMHC

Recognition by the T-cell receptor (TCR) on CD8+ cytotoxic T lymphocytes (CTLs), which triggers the release of cytotoxic granules (perforin/granzyme) and pro-inflammatory cytokines (IFN-gamma, TNF-alpha) to lyse the CMV-infected cell (PubMed: 8623487).