Tumor-associated antigen presented on Major Histocompatibility Complex (TAA-MHC complex)

Tumor-associated antigens (TAAs) presented on Major Histocompatibility Complex (MHC) molecules represent a critical interface between the immune system and malignant cells. These targets consist of short peptide fragments, derived from intracellular proteins, that are loaded onto MHC Class I or II molecules and displayed on the cell surface for surveillance by T-cell receptors (TCRs) (Abbas et al., 2021). In oncology, these antigens can be classified into neoantigens (derived from somatic mutations), overexpressed self-antigens, or cancer-testis antigens (Vigneron, 2015). Therapeutic interventions such as TCR-engineered T-cells (TCR-T) and bispecific T-cell engagers are designed to specifically bind these complexes to trigger a potent anti-tumor immune response (FDA, 2024). Unlike traditional antibody targets that require surface protein expression, TAA-MHC complexes allow the immune system to identify the internal proteome of the cancer cell. However, the effectiveness of these therapies is often limited by HLA restriction, where a drug is only compatible with patients possessing specific MHC alleles, and the potential for immune evasion through the loss of MHC expression (Sahin & Türeci, 2018).

Other names

Tumor-specific antigenNeoantigenCancer-testis antigenMHC-peptide complexHLA-peptide complexMHC-restricted antigen

T-cell receptor (TCR) mediated recognition of peptide-MHC complexes leading to cytotoxic T-lymphocyte activation and tumor cell lysis (FDA, 2024).