Tumor-associated peptide-human leukocyte antigen complex (pHLA)

The tumor-associated peptide-human leukocyte antigen (pHLA) complex is a molecular assembly consisting of a tumor-derived peptide fragment bound to a human leukocyte antigen (HLA) molecule, serving as the primary recognition element for T-cell receptors (TCRs) (Source: Nature Reviews Drug Discovery, 2021). These complexes allow the immune system to monitor the intracellular proteome, as peptides from mutated, overexpressed, or lineage-specific proteins are processed and presented on the cell surface via the MHC Class I or II pathways (Source: PubMed, PMID: 31434610). In oncology, pHLA complexes are targeted by innovative therapies such as TCR-engineered T-cells (TCR-T) and bispecific T-cell engagers (ImmTACs), which can address intracellular targets that are inaccessible to conventional monoclonal antibodies (Source: NIH, National Cancer Institute). Notable examples include Tebentafusp, which targets the gp100 peptide-HLA-A*02:01 complex in uveal melanoma, and Afamitresgene autoleucel, which targets MAGE-A4 (Source: FDA.gov). Despite their high specificity, these targets pose significant challenges due to HLA restriction, where a drug is only effective in patients with specific HLA genotypes, and the potential for fatal off-target toxicity if the target peptide mimics sequences found in healthy tissues (Source: Journal for ImmunoTherapy of Cancer, 2020).

Other names

Peptide-MHC complexpMHCTumor-specific antigen-HLA complexNeoantigen-HLA complexAntigen-HLA complex

T-cell receptor (TCR) mediated recognition and subsequent T-cell activation and tumor cell lysis