Viral peptide-HLA class I and class II complexes (Cytomegalovirus, Epstein-Barr virus, Adenovirus) (pHLA complexes)

Viral peptide-HLA class I and class II complexes are the fundamental molecular structures recognized by the adaptive immune system on the surface of cells infected with cytomegalovirus (CMV), Epstein-Barr virus (EBV), and adenovirus (AdV). These complexes are formed when viral proteins are processed into short peptides and loaded onto Human Leukocyte Antigen (HLA) molecules within the infected cell before being transported to the plasma membrane (1.1.2, 1.4.1). HLA class I molecules typically present these peptides to CD8+ cytotoxic T cells, while HLA class II molecules present them to CD4+ T cells, facilitating a coordinated immune response (1.1.2, 1.4.4). In patients with weakened immune systems, such as those receiving hematopoietic stem cell or solid organ transplants, the absence of effective T-cell recognition of these complexes can lead to severe opportunistic infections and malignancies like post-transplant lymphoproliferative disease (PTLD) (1.2.5, 1.3.5). Therapeutic interventions, such as allogeneic virus-specific T cells (VSTs) like tabelecleucel and posoleucel, are engineered or selected to specifically bind these viral pHLA complexes via their T-cell receptors (TCRs) (1.2.1, 1.3.1). This binding triggers the release of cytotoxic granules, such as perforin and granzymes, which selectively destroy the infected cells while sparing healthy tissue (1.1.2, 1.4.1). Consequently, these complexes serve as critical targets for restoring antiviral immunity and managing life-threatening viral complications in transplant recipients (1.3.5, 1.4.4).

Other names

Viral peptide-MHC complexesCMV/EBV/AdV pMHC complexesViral immunopeptidomepMHC class I and II complexesViral antigen-HLA complexes

Recognition by T-cell receptors (TCRs) on cytotoxic T lymphocytes (CTLs), leading to the activation of immune effector functions and lysis of infected cells.