Tyrosinase-derived peptide-MHC class I complex (Tyrosinase-pMHC)

Tyrosinase-derived peptide-MHC class I complexes are specific molecular targets found on the surface of melanoma cells, formed when peptides from the tyrosinase enzyme are processed and presented by Major Histocompatibility Complex (MHC) molecules. Tyrosinase is a copper-containing enzyme (UniProt P14679) that catalyzes the rate-limiting steps of melanin biosynthesis and is highly expressed in melanocytes and melanoma cells. Because it is a differentiation antigen, its expression is largely restricted to the melanocytic lineage, making its MHC-presented epitopes attractive targets for T-cell based immunotherapies (PubMed: 15507677). Therapeutic strategies targeting these complexes include T-cell receptor (TCR) engineered T-cells and bispecific T-cell engagers like IMC-F10V, which redirect the immune system to kill cells displaying the specific tyrosinase peptide (e.g., YMDGTMSQV). While effective against tumor cells, these therapies often encounter safety challenges due to the presence of tyrosinase in healthy melanocytes. This can lead to on-target, off-tumor toxicities such as vitiligo (depigmentation of the skin) and uveitis (inflammation of the eye), which serve as both safety concerns and potential indicators of therapeutic activity (PubMed: 22555444). Monitoring for these autoimmune reactions is a standard part of clinical protocols for therapies targeting these epitopes. The HLA-A*02:01 allele is the most common MHC molecule used to present these epitopes in clinical development.

Other names

Tyrosinase-MHC complexMelanoma-associated antigen tyrosinase epitopesTYR-pMHCHLA-A*02:01/Tyrosinase(369-377)Tyrosinase-derived epitopes

T-cell receptor (TCR) mediated recognition of the peptide-MHC complex leading to T-cell activation and lysis of the target cell.