Peptide-Human Leukocyte Antigen class I complexes presenting tumor-associated antigens (PRAME, NY-ESO-1, Survivin, MAGE-A4, SSX2, WT1) (pHLA-I (TAA/CTA))

Peptide-Human Leukocyte Antigen (HLA) class I complexes are molecular assemblies on the surface of nucleated cells that present intracellularly derived peptides to CD8+ T-cells [1]. These complexes consist of a polymorphic HLA heavy chain, beta-2 microglobulin, and a peptide ligand, typically 8-11 amino acids in length, generated by the proteasomal degradation of cellular proteins [2]. In the context of oncology, these complexes present peptides derived from tumor-associated antigens (TAAs) such as Survivin and WT1, or cancer-testis antigens (CTAs) like PRAME, NY-ESO-1, MAGE-A4, and SSX2 [3]. These antigens are characterized by high expression in various malignancies and highly restricted expression in normal adult tissues, providing a therapeutic window for immune intervention [4]. Drugs targeting these specific pHLA complexes, such as T-cell receptor (TCR)-engineered T-cells and TCR-bispecific molecules, are designed to recognize the peptide-HLA combination with high specificity and affinity, bypassing the need for surface protein expression [5]. This approach allows the immune system to target the intracellular proteome, which contains a vast array of potential tumor-specific targets not accessible to conventional antibody-based therapies [6].

Other names

pHLA class I complexesTumor-associated antigen (TAA) peptide-MHC complexesCancer-testis antigen (CTA) peptide-HLA complexespMHC complexes

T-cell receptor (TCR) mediated recognition of specific peptide-HLA complexes on the tumor cell surface, triggering cytotoxic T-lymphocyte (CTL) activation, granzyme/perforin release, and apoptosis of the target cell.