T cell receptor recognizing MAGE-A3 peptide presented by HLA-A1 (TCR MAGE-A3/HLA-A1)

The T cell receptor (TCR) recognizing the MAGE-A3.A1–HLA-A1 complex is an engineered immune receptor designed for adoptive T-cell therapy against MAGE-A3-expressing malignancies. MAGE-A3 (Melanoma-associated antigen A3) is a prominent cancer-testis antigen (CTA) that is typically expressed in various cancers, including melanoma, multiple myeloma, and non-small cell lung cancer, but is restricted to immune-privileged sites like the testes in healthy individuals (UniProt P43357; PubMed: 23775481). This specific TCR is engineered to recognize the MAGE-A3-derived peptide (EVDPIGHLY) when presented by the Human Leukocyte Antigen (HLA)-A*01:01 MHC class I molecule (PubMed: 23580313). By transducing patient-derived T cells with this TCR, the immune system is redirected to identify and eliminate tumor cells expressing the MAGE-A3/HLA-A1 complex. Clinical development of this target has provided critical insights into the safety of TCR-engineered therapies. In early-phase clinical trials, patients treated with affinity-enhanced MAGE-A3/HLA-A1 TCR-T cells experienced severe, and in some cases fatal, neurological toxicity (PubMed: 23580313). This adverse event was later attributed to off-target cross-reactivity with MAGE-A12, a related protein expressed in human brain tissue that was not initially identified as a risk during preclinical screening (PubMed: 23580313). Consequently, this target serves as a landmark case in immunotherapy, highlighting the necessity for exhaustive cross-reactivity profiling against the human proteome to prevent off-target, off-tumor effects during the development of high-affinity TCRs.

Other names

MAGE-A3-specific T-cell receptorHLA-A*01-restricted MAGE-A3 TCRAnti-MAGE-A3 TCRMAGE-A3/HLA-A1 TCR

The mechanism of action involves the genetic modification of autologous T cells to express a specific T-cell receptor (TCR) that binds to the MAGE-A3 peptide (EVDPIGHLY) presented by HLA-A*01:01. Upon recognition of this complex on the surface of cancer cells, the engineered T cells are activated to release cytotoxic molecules such as perforin and granzymes, as well as cytokines like IFN-gamma and TNF-alpha, resulting in the targeted destruction of the tumor cells.