Tumor-associated antigen-derived peptide-HLA complex (pHLA)

Tumor-associated antigen (TAA)-derived peptide-HLA complexes are the primary targets for T-cell-mediated immunity against cancer, representing the molecular interface between malignant cells and the cellular immune system (NIH, 2016). These complexes consist of short peptide fragments, typically 8-11 amino acids in length, derived from intracellular proteins that are processed by the proteasome and presented on the cell surface by Human Leukocyte Antigen (HLA) Class I molecules (Frontiers, 2023). Unlike traditional antibody targets that must be surface-expressed proteins, peptide-HLA complexes allow the immune system to see the internal proteome of a cell, including mutated neoantigens, overexpressed self-antigens, and cancer-testis antigens (NIH, 2021). In the context of disease, cancer cells often present unique or overexpressed peptides that can be recognized as foreign by T-cells, though tumors frequently employ mechanisms like HLA downregulation to evade this recognition (NIH, 2016). Therapeutic strategies targeting these complexes include engineered T-cell receptor (TCR) T-cell therapies, bispecific T-cell engagers (such as ImmTACs), and TCR-like antibodies, which are designed to bind the specific peptide-HLA combination with high affinity (Liv Hospital, 2024). While highly promising for treating solid tumors, these therapies require precise patient selection based on HLA genotype and antigen expression (AACR, 2025). Significant safety challenges include potential off-target toxicity due to peptide mimicry in healthy tissues and the risk of cytokine release syndrome following potent T-cell activation (NIH, 2023).

Other names

Peptide-MHC complexpMHCpHLATumor-specific peptide-HLA complexTAA-peptide-HLA complexHLA-peptide complexMHC-peptide complex

T-cell receptor (TCR) mediated recognition, bispecific T-cell redirection (ImmTACs), and adoptive cell therapy (TCR-T) targeting specific peptide-HLA combinations to induce tumor cell lysis.