Peptide-Major Histocompatibility Complex presenting melanoma-associated tumor-associated antigens (pMHC)

Peptide-Major Histocompatibility Complex (pMHC) complexes on melanoma cells are specialized molecular structures that present intracellular tumor-associated antigens (TAAs) to the immune system (Janeway et al., Immunobiology, 2001). These complexes are formed when degraded protein fragments from antigens like gp100, MAGE-A4, or NY-ESO-1 are loaded onto HLA molecules, primarily MHC Class I, and transported to the cell surface (Nature Reviews Cancer, 2021). Their biological role is to facilitate the recognition of malignant cells by CD8+ T-cells through the T-cell receptor (TCR). In melanoma therapy, these pMHCs are targeted by novel modalities such as TCR-engineered T-cells (e.g., afamitresgene autoleucel) and bispecific T-cell engagers (e.g., tebentafusp) to induce potent immune-mediated tumor lysis (New England Journal of Medicine, 2021). Because these targets are HLA-restricted, their clinical application is limited to patients with specific genotypes, such as HLA-A*02:01. A significant therapeutic challenge involves on-target, off-tumor toxicity, as many melanoma TAAs are also expressed in healthy melanocytes found in the skin, eye, and inner ear (Journal of Clinical Oncology, 2022). Additionally, tumors can evade treatment by downregulating HLA expression or through the loss of the specific antigen (Cancer Discovery, 2019).

Other names

Melanoma pMHCHLA-peptide complexTumor-specific pMHCMHC-restricted tumor antigenpMHC-TAA

T-cell redirection via engineered T-cell receptor (TCR) binding to peptide-MHC complexes