title: HER-2/neu and hTERT cryptic epitopes as novel targets for broad spectrum tumor immunotherapy.
abstract: Tolerance to tumor-nonmutated self proteins represents a major obstacle for successful cancer immunotherapy. Since this tolerance primarily concerns dominant epitopes, we hypothesized that targeting cryptic epitopes that have a low affinity for HLA could be an efficient strategy to breach the tolerance to tumor Ags. Using the P1Y heteroclitic peptide approach, we identified low affinity cryptic HLA-A*0201-restricted epitopes derived from two widely expressed tumor Ags, HER-2/neu and hTERT. The P1Y variants of four HER-2/neu (neu(391), neu(402), neu(466), neu(650))- and two hTERT (hTERT(572) and hTERT(988))-derived low affinity peptides exhibited strong affinity for HLA-A*0201 and stimulated specific CTL from healthy donor PBMCs. These CTL specifically recognized HER-2/neu- and hTERT-expressing tumor cells of various histological origins. In vivo studies showed that HLA-A*0201 transgenic HHD mice vaccinated with the P1Y variant peptides generated CTL that specifically lysed Ag-expressing tumor cells, thus recognizing the cognate endogenous Ags. These results suggest that heteroclitic variants of low affinity, cryptic epitopes of widely expressed tumor Ags may serve as valid tools for tumor immunotherapy.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale Unité 487, Institut Gustave Roussy, Villejuif, France.
authors.forename: Antonio
authors.initials: A
authors.lastname: Scardino
authors.forename: David-Alexandre
authors.initials: DA
authors.lastname: Gross
authors.forename: Pedro
authors.initials: P
authors.lastname: Alves
authors.forename: Joachim L
authors.initials: JL
authors.lastname: Schultze
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Graff-Dubois
authors.forename: Olivier
authors.initials: O
authors.lastname: Faure
authors.forename: Sophie
authors.initials: S
authors.lastname: Tourdot
authors.forename: Salem
authors.initials: S
authors.lastname: Chouaib
authors.forename: Lee M
authors.initials: LM
authors.lastname: Nadler
authors.forename: François A
authors.initials: FA
authors.lastname: Lemonnier
authors.forename: Robert H
authors.initials: RH
authors.lastname: Vonderheide
authors.forename: Angelo A
authors.initials: AA
authors.lastname: Cardoso
authors.forename: Kostas
authors.initials: K
authors.lastname: Kosmatopoulos
mesh_terms: D000818:Animals; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000276:immunology*; D002460:Cell Line; D004268:DNA-Binding Proteins; D000939:Epitopes; D015234:HLA-A Antigens / Q000276:immunology*; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D051379:Mice; D009369:Neoplasms / Q000628:therapy*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D019098:Telomerase / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D004268:DNA-Binding Proteins; D000939:Epitopes; D015234:HLA-A Antigens; D018719:Erb-b2 Receptor Tyrosine Kinases; D019098:Telomerase