Tumor-associated antigen-Major Histocompatibility Complex class I (TAA-MHC I) (TAA-MHC I)

Tumor-associated antigen (TAA) presented by MHC class I complexes are pivotal targets in cancer immunotherapy, representing the primary mechanism by which the immune system identifies malignant cells [1]. These complexes consist of a short peptide fragment, derived from intracellular proteins, nested within the binding groove of a Major Histocompatibility Complex (MHC) class I molecule [2]. On the surface of tumor cells, these pMHC complexes act as specific markers that allow CD8+ cytotoxic T lymphocytes to recognize and eliminate the cancer cell via T-cell receptor (TCR) binding [2]. Dendritic cells facilitate this process through cross-presentation, where they internalize tumor antigens and display them on their own MHC class I molecules to prime naive T cells [2]. Therapeutic interventions such as TCR-engineered T-cell (TCR-T) therapies and bispecific T-cell engagers (e.g., Tebentafusp) are designed to specifically target these complexes with high affinity [3, 4]. Additionally, cancer vaccines aim to increase the density of these complexes on dendritic cells to enhance the endogenous anti-tumor immune response [1]. A significant challenge in targeting these antigens is the risk of off-target toxicity if the targeted peptide is shared with healthy tissues, a phenomenon known as molecular mimicry [4]. Furthermore, tumors often escape immune detection by downregulating MHC class I expression or mutating the antigen processing machinery [2].

Other names

pMHC complexPeptide-MHC class I complexTumor-specific antigen-MHC complexHLA-restricted tumor antigenCancer-testis antigen-MHC complex

Therapeutic agents target the specific peptide-MHC complex to facilitate T-cell receptor (TCR) mediated recognition and subsequent cytotoxic destruction of tumor cells.