title: An altered peptide ligand for naïve cytotoxic T lymphocyte epitope of TRP-2(180-188) enhanced immunogenicity.
abstract: Tyrosinase-related protein-2 (TRP-2) is a non-mutated melanocyte differentiation antigen. The TRP-2-recognizing CD8(+) T cells can evoke immune responses to melanoma in both humans and mice. Developing epitopes with amino acid replacements in their sequences might improve the low immunogenicity against this 'self' tumor antigen. We designed altered peptide ligands (APLs) of TRP-2((180-188)) (SVYDFFVWL) with preferred primary and auxiliary HLA-A*0201 molecule anchor residue replacement. These APLs were screened for MHC-affinity by affinity prediction plots and molecular dynamics simulation, and analyzed in vitro for stability and binding-affinity to molecular HLA-A*0201. We also investigated the CTLs activities induced by TRP-2 wild-type epitope and the APLs both in vitro in human PBMCs and HLA-A2.1/K(b) transgenic mice. The results indicate that TRP-2 2M analog simultaneously had stronger binding-affinity and a lower dissociation rate to HLA-A*0201, than wild-type peptide. In addition, the analog 2M was superior to other APLs and wild-type epitope in terms of immunological efficacy ex vivo as measured by the ELISPOT assays of IFN-gamma and granzyme B. These results demonstrate that TRP-2 2M is an agonist epitope that can induce anti-tumor immunity superior to its wild-type epitope, and has potential application in peptide-mediated immunotherapy.
authors.affiliation: Institute of Immunology PLA, Third Military Medical University, Shapingba, Chongqing 400038, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Tang
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Lin
authors.forename: Bing
authors.initials: B
authors.lastname: Ni
authors.forename: Jing
authors.initials: J
authors.lastname: Wei
authors.forename: Junfeng
authors.initials: J
authors.lastname: Han
authors.forename: Huiming
authors.initials: H
authors.lastname: Wang
authors.forename: Yuzhang
authors.initials: Y
authors.lastname: Wu
mesh_terms: D019943:Amino Acid Substitution / Q000276:immunology; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D020126:Brefeldin A / Q000494:pharmacology; D045744:Cell Line, Tumor; D003713:Dendritic Cells; D004306:Dose-Response Relationship, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000187:drug effects / Q000276:immunology*; D015234:HLA-A Antigens / Q000187:drug effects / Q000276:immunology; D015789:HLA-A2 Antigen; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D019746:Intramolecular Oxidoreductases / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008024:Ligands; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology; D051379:Mice; D008822:Mice, Transgenic; D008958:Models, Molecular; D010446:Peptide Fragments / Q000737:chemistry / Q000276:immunology* / Q000494:pharmacology; D012016:Reference Values; D013329:Structure-Activity Relationship; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology*
chemical_list: D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D008024:Ligands; D008565:Membrane Proteins; D010446:Peptide Fragments; C500290:peptide SVYDFFVWL; D020126:Brefeldin A; D007371:Interferon-gamma; D019746:Intramolecular Oxidoreductases; C042501:dopachrome isomerase