title: Identification of a new hTERT-derived HLA-A*0201 restricted, naturally processed CTL epitope.
abstract: By the use of a neural network capable of performing quantitative predictions of peptides binding to HLA-A*0201 molecules, we identified a number of nonamer peptides derived from the catalytic subunit of telomerase, human telomerase reverse transcriptase (hTERT). Five nonimmunogenic peptides with measured binding affinities for HLA-A*0201 ranging from 155 to 1,298 nM were modified at the P1, P2 and P9 positions, respectively, to achieve stronger HLA-A*0201 binding. One peptide, mp30-38 (mp30), with an L to V substitution at position 9 was subsequently found to be immunogenic in mp30 immunized HLA-A*0201/H2K(b) or HHD transgenic mice. The T cell reactivity obtained was directed against both the mp30 and against the unmodified p30. Anti-mp30 specific T cells generated in HLA-A*0201 transgenic mice were dependent on TCR-CD8/MHC-I alpha3 binding and therefore not capable of recognizing mp30-pulsed human HLA-A*0201(+) cells or murine HLA-A*0201 transfectants. In order to show reactivity against naturally processed peptide in human tumor cells, an hTERT positive HLA-A*0201 negative colon carcinoma cell line (CCL220) was transfected with an HLA-A*0201/H2K(b) cDNA construct and used as target in ELISPOT and cytotoxicity assays. The data show that T cells from mp30 immunized HHD transgenic mice react specifically against the CCL220 transfectant indicating that p30 is naturally processed. In conclusion, we have identified a new CTL HLA-A*0201 restricted hTERT epitope, which is now, included in an ongoing phase 2 vaccine trial of patients with disseminated cancer.
authors.affiliation: Laboratory of Cellular Immunology, Department of International Health, Immunology and Microbiology, The Panum Institute, University of Copenhagen, Blegdamsvej 3, 2200, Copenhagen N, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Thorn
authors.forename: Mingjun
authors.initials: M
authors.lastname: Wang
authors.forename: Henrik
authors.initials: H
authors.lastname: Kløverpris
authors.forename: Esben G W
authors.initials: EG
authors.lastname: Schmidt
authors.forename: Anders
authors.initials: A
authors.lastname: Fomsgaard
authors.forename: Lynn
authors.initials: L
authors.lastname: Wenandy
authors.forename: Annika
authors.initials: A
authors.lastname: Berntsen
authors.forename: Søren
authors.initials: S
authors.lastname: Brunak
authors.forename: Søren
authors.initials: S
authors.lastname: Buus
authors.forename: Mogens H
authors.initials: MH
authors.lastname: Claesson
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D017951:Antigen Presentation; D015153:Blotting, Western; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D045744:Cell Line, Tumor; D018984:Epitopes, T-Lymphocyte / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D015234:HLA-A Antigens / Q000378:metabolism*; D015789:HLA-A2 Antigen; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D011485:Protein Binding; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D019098:Telomerase / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology
chemical_list: D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; C435939:HLA-A*02:01 antigen; D015789:HLA-A2 Antigen; D010446:Peptide Fragments; C523666:hTERT mp30-38 peptide; D019098:Telomerase