Human leukocyte antigen-viral peptide complex (pMHC) (pMHC)

The Human Leukocyte Antigen (HLA)-viral peptide complex is a fundamental immunological structure that presents intracellular viral fragments to the immune system. When a cell is infected by viruses such as Adenovirus, Cytomegalovirus (CMV), or Epstein-Barr Virus (EBV), viral proteins are proteolytically degraded into short peptides and loaded onto HLA Class I or II molecules for surface display (Source: NIH/NCBI). This complex acts as a molecular "red flag," allowing the T-cell receptor (TCR) of circulating T cells to recognize and initiate the destruction of the infected cell (Source: PubMed). In clinical practice, this target is exploited through the administration of virus-specific T-cells (VSTs) or TCR-engineered therapies, which are designed to bind specifically to these pMHC complexes (Source: Allovir, Atara Biotherapeutics). These therapies are especially critical for treating refractory viral infections in immunocompromised patients, such as those undergoing hematopoietic stem cell transplants. The primary challenge in targeting these complexes lies in the high polymorphism of HLA genes and the risk of "off-target, off-tumor" toxicity if the therapeutic TCR cross-reacts with similar-looking self-peptides presented on healthy tissues (Source: Nature Reviews Immunology).

Other names

MHC-peptide complexViral antigen-HLA complexpMHC Class IpMHC Class IIVirus-specific antigenHLA-peptide complex

T-cell receptor (TCR) mediated recognition of the peptide-HLA complex, triggering cytotoxic T-lymphocyte (CTL) activation and apoptosis of the target cell.