Melanocyte protein PMEL (gp100) modified epitope (KGPRNQDWL) (gp100KGP)

The gp100KGP epitope is a modified, heteroclitic peptide derived from the melanocyte differentiation antigen gp100 (also known as PMEL or PMEL17) [1.2.1, 1.4.1]. It specifically refers to the amino acid sequence KGPRNQDWL, which is an altered version of the native murine gp100:25-33 epitope (EGSRNQDWL) [1.2.1, 1.2.4]. The modification involves substituting the first and third amino acids to enhance the binding affinity and stability of the peptide when presented by the MHC class I molecule H-2Db [1.1.2, 1.2.1]. This increased immunogenicity is designed to overcome immune self-tolerance, allowing for the activation of T cells that would otherwise remain quiescent [1.2.4, 1.2.5]. In preclinical research, the KGP epitope is frequently delivered using viral vectors, such as murine cytomegalovirus (MCMV-gp100KGP), to study cancer immunotherapy [1.2.1, 1.2.3]. These vaccines induce a robust, polyfunctional CD8+ T-cell response that can undergo 'T-cell inflation,' providing long-lasting surveillance against tumor cells [1.2.2, 1.2.4]. The induced T cells cross-react with the native gp100 antigen expressed on melanoma cells, leading to effective tumor rejection and protection against metastasis [1.2.1, 1.2.4]. However, because gp100 is also expressed in normal melanocytes, targeting this epitope can lead to autoimmune side effects such as vitiligo [1.3.2, 1.4.1]. This epitope serves as a critical model for developing 'altered peptide ligand' (APL) strategies to improve the efficacy of cancer vaccines [1.1.2, 1.2.5].

Other names

KGPRNQDWLgp100:25-33(KGP)Modified gp100 epitopeAltered peptide ligand gp100gp100KGP

Induction of tumor-specific CD8+ T-cell response via MHC class I-restricted antigen presentation and overcoming immune self-tolerance.