Cytomegalovirus peptide–HLA class II complex (CMV pMHC-II)

Cytomegalovirus (CMV) peptide–HLA class II complexes are molecular assemblies expressed on the surface of professional antigen-presenting cells (APCs), such as dendritic cells, macrophages, and B cells. These complexes consist of a processed peptide fragment derived from CMV viral proteins, such as pp65 or glycoprotein B (gB), non-covalently bound within the peptide-binding groove of a Human Leukocyte Antigen (HLA) class II molecule (e.g., HLA-DR, DQ, or DP). Their primary biological role is to present viral antigens to the T-cell receptors (TCRs) of CD4+ T helper cells, which is a critical step in orchestrating the adaptive immune response and maintaining viral latency. In clinical medicine, these complexes serve as the primary target for CMV-specific adoptive T-cell therapies and vaccines, particularly in immunocompromised patients such as hematopoietic stem cell or solid organ transplant recipients. By targeting these specific pMHC-II complexes, therapeutic interventions aim to restore or enhance the patient's cellular immunity to control CMV replication and prevent symptomatic disease.

Other names

CMV peptide-MHC class II complexCytomegalovirus antigen-HLA-II complexCMV pMHCIIHuman cytomegalovirus peptide-HLA class II complex

Recognition by the T-cell receptor (TCR) of CD4+ T lymphocytes, leading to the activation of helper T-cell responses and coordination of the adaptive immune system against CMV-infected cells.