Peptide-Major Histocompatibility Complex class I presenting Cytomegalovirus and Epstein-Barr Virus epitopes (pMHC-I (CMV/EBV))

Peptide-Major Histocompatibility Complex (pMHC) class I complexes presenting Cytomegalovirus (CMV) and Epstein-Barr Virus (EBV) epitopes are essential structures for the immune system's recognition of virally infected cells (Houghteling & Belani, 2019). These complexes are formed when intracellular viral proteins, such as CMV pp65 or EBV nuclear antigens (EBNA), are processed into short peptides and loaded onto MHC class I molecules for surface display (UniProt, 2023). In the context of therapeutic intervention, these pMHC complexes serve as the primary targets for adoptive T-cell therapies, including virus-specific T cells (VSTs) and TCR-engineered T cells (Atara Biotherapeutics, 2022). These therapies are particularly vital for immunocompromised patients, such as hematopoietic stem cell transplant recipients, who are at high risk for CMV reactivation or EBV-associated post-transplant lymphoproliferative disorder (PTLD) (AlloVir, 2023). By specifically binding to these viral pMHC complexes, therapeutic T cells can selectively eliminate infected or malignant cells while sparing healthy tissue (Prockop et al., 2020). The efficacy of these treatments is highly dependent on the specific HLA allele of the patient, as MHC molecules are highly polymorphic and dictate which viral peptides can be presented (StatPearls, 2023).

Other names

CMV/EBV pMHC complexesHLA-peptide complexes (CMV/EBV)MHC-I-restricted viral antigensVirus-specific MHC-peptide complexes

Recognition by specific T-cell receptors (TCRs) on CD8+ cytotoxic T cells, leading to the release of perforins and granzymes and subsequent apoptosis of the target cell.