Cytomegalovirus antigen-HLA class II complex (CMV-HLA-II)

The Cytomegalovirus (CMV) antigen-HLA class II complex is a molecular assembly formed when viral peptides, such as those derived from the pp65 (UL83) or glycoprotein B (gB) proteins, are processed and presented on the surface of antigen-presenting cells (APCs) via Human Leukocyte Antigen (HLA) class II molecules like HLA-DR, HLA-DQ, or HLA-DP (UniProt P06725; PubMed: 12134020). This complex serves as the specific recognition element for the T-cell receptors (TCRs) of CD4+ T lymphocytes, which are essential for controlling CMV infection through the secretion of pro-inflammatory cytokines and direct cytolytic activity (PubMed: 16339316). In clinical settings, particularly following hematopoietic stem cell or solid organ transplantation, the failure of the host immune system to recognize these complexes often leads to viral reactivation and severe systemic disease (PubMed: 30642819). Consequently, this complex is a primary target for immunotherapy, including the development of adoptive T-cell therapies like posoleucel and next-generation vaccines like mRNA-1647 that aim to restore or enhance HLA class II-restricted antiviral immunity (AlloVir; Moderna). The therapeutic focus on this complex is driven by the need to provide long-term protection against CMV in immunocompromised populations where traditional antivirals may be toxic or ineffective.

Other names

CMV peptide-MHC class II complexCMV pMHC-IIHuman cytomegalovirus antigen-HLA class II complexCMV-HLA-DR complexCMV-HLA-DQ complexCMV-HLA-DP complex

Activation of CD4+ T-cells via T-cell receptor (TCR) recognition of the peptide-HLA complex, leading to cytokine release and viral clearance.