Human leukocyte antigen DRB1*04:01 (HLA-DRB1*04:01) presenting glycoprotein 100 (gp100:44-59) epitope to CD4+ T-cell receptor (TCR) (HLA-DRB1*04:01/gp100:44-59/TCR)

The Human leukocyte antigen DRB1*04:01 (HLA-DRB1*04:01) presenting glycoprotein 100 (gp100:44-59) epitope to CD4+ T-cell receptor (TCR) is a tripartite molecular complex that serves as a critical target for melanoma immunotherapy. HLA-DRB1*04:01 is a Major Histocompatibility Complex (MHC) class II allele that presents processed peptide fragments to CD4+ T helper cells (IPD-IMGT/HLA Database). The gp100:44-59 epitope, with the sequence WNRQLYPEWTEAQRLD, is derived from the melanocyte-specific protein PMEL (gp100), which is highly expressed in most melanoma tumors (UniProt P17683). When a cognate TCR binds to this specific peptide-MHC complex, it initiates a signaling cascade that activates the CD4+ T cell, leading to the production of cytokines such as interferon-gamma that enhance the overall anti-tumor immune response (PubMed PMID 10946282). This interaction is the basis for developing TCR-engineered T-cell therapies and therapeutic vaccines designed to selectively eliminate melanoma cells in patients carrying the HLA-DRB1*04:01 allele (PubMed PMID 15123715). Because gp100 is also expressed in normal melanocytes, therapeutic strategies targeting this complex must be carefully monitored for autoimmune side effects, such as vitiligo or uveitis, resulting from the destruction of healthy pigmented tissues (PubMed PMID 21149650). Current clinical research focuses on optimizing TCR affinity and ensuring the safety of these potent immunotherapeutic interventions.

Other names

HLA-DR4/gp100:44-59 complexMHC Class II-gp100-TCR complexPMEL:44-59/HLA-DRB1*04:01HLA-DRB1*04:01-PMEL complex

The T-cell receptor (TCR) specifically recognizes and binds to the gp100:44-59 peptide presented within the groove of the HLA-DRB1*04:01 MHC class II molecule, triggering T-cell activation, cytokine secretion, and the orchestration of an adaptive immune response against cells expressing the gp100 antigen.