Tumor-associated peptide-HLA class I complex (pHLA-I)

Tumor-associated peptide-HLA class I complexes (pHLA-I) are molecular assemblies on the surface of malignant cells that serve as the primary targets for T-cell-mediated immunity. These complexes consist of a polymorphic Human Leukocyte Antigen (HLA) class I heavy chain, a beta-2 microglobulin subunit, and a short peptide (typically 8-11 amino acids) derived from intracellular proteins (1.2.1, 1.4.1). In cancer cells, these peptides often originate from mutated proteins (neoantigens), overexpressed self-antigens, or cancer-testis antigens that are not typically presented by healthy somatic cells (1.2.4, 1.2.5). Because HLA molecules present the internal proteome to the cell surface, they allow the immune system to detect intracellular oncogenic drivers that are otherwise inaccessible to traditional antibody-based therapies (1.1.3, 1.3.1). Modern immunotherapies, such as TCR-engineered T-cells (TCR-T) and Immune Mobilizing Monoclonal TCRs Against Cancer (ImmTACs), are designed to recognize these specific pHLA-I targets with high affinity and specificity (1.2.1, 1.2.5). However, the high degree of HLA polymorphism and the risk of cross-reactivity with similar peptides in normal tissues present significant challenges for broad clinical application and safety (1.2.1, 1.1.4).

Other names

Peptide-MHC class I complexpMHC-ITumor-specific peptide-HLA complexTA-pHLACancer immunopeptidomeTumor antigen-HLA complex

T-cell redirection and activation via engineered T-cell receptors (TCRs) or bispecific molecules that bind specifically to the peptide-HLA complex on the tumor cell surface, leading to directed cytotoxicity (1.2.1, 1.4.1).