Viral Peptide-Major Histocompatibility Complex (pMHC) (pMHC)

Peptide-Major Histocompatibility Complex (pMHC) molecules are essential surface structures that present intracellularly derived peptides to the immune system (Janeway et al., Immunobiology, 2001). In cells infected with viruses such as Cytomegalovirus (CMV), Epstein-Barr Virus (EBV), Adenovirus, and BK Virus, these complexes display viral-derived epitopes to CD8+ cytotoxic T lymphocytes (CTLs) (Haque et al., Lancet Oncol, 2007). This presentation is the fundamental mechanism by which the immune system distinguishes "self" from "non-self," triggering a targeted immune response against the infected cell. In clinical settings, particularly for immunocompromised transplant recipients, these pMHC complexes are the primary targets for adoptive T-cell therapies (Prockop et al., J Clin Invest, 2020). Drugs like Tabelecleucel (Ebvallo) and investigational therapies like Posoleucel (ALVR105) consist of T-cells engineered or selected to recognize these specific viral pMHCs, facilitating the clearance of persistent or reactivated infections (AlloVir, 2023; EMA, 2022). The therapeutic efficacy of these treatments depends heavily on the correct matching of Human Leukocyte Antigen (HLA) alleles between the donor T-cells and the patient's infected cells to ensure proper pMHC recognition.

Other names

HLA-peptide complexViral antigen-MHC complexMHC-restricted viral antigenspMHC complexCMV/EBV/Adv/BKV pMHC complexes

Recognition by T-cell receptors (TCRs) on cytotoxic T lymphocytes (CTLs), leading to direct lysis of infected cells and cytokine release.