title: Spontaneous CD8 T cell responses against the melanocyte differentiation antigen RAB38/NY-MEL-1 in melanoma patients.
abstract: The melanocyte differentiation Ag RAB38/NY-MEL-1 was identified by serological expression cloning (SEREX) and is expressed in the vast majority of melanoma lesions. The immunogenicity of RAB38/NY-MEL-1 has been corroborated previously by the frequent occurrence of specific Ab responses in melanoma patients. To elucidate potential CD8 T cell responses, we applied in vitro sensitization with overlapping peptides spanning the RAB38/NY-MEL-1 protein sequence and the reverse immunology approach. The identified peptide RAB38/NY-MEL-1(50-58) exhibited a marked response in ELISPOT assays after in vitro sensitization of CD8 T cells from HLA-A *0201(+) melanoma patients. In vitro digestion assays using purified proteasomes provided evidence of natural processing of RAB38/NY-MEL-1(50-58) peptide. Accordingly, monoclonal RAB38/NY-MEL-1(50-58)-specific T cell populations were capable of specifically recognizing HLA-A2(+) melanoma cell lines expressing RAB38/NY-MEL-1. Applying fluorescent HLA-A2/RAB38/NY-MEL-1(50-58) multimeric constructs, we were able to document a spontaneously developed memory/effector CD8 T cell response against this peptide in a melanoma patient. To elucidate the Ag-processing pathway, we demonstrate that RAB38/NY-MEL-1(50-58) is produced efficiently by the standard proteasome and the immunoproteasome. In addition to the identification of a RAB38/NY-MEL-1-derived immunogenic CD8 T cell epitope, this study is instrumental for both the onset and monitoring of future RAB38/NY-MEL-1-based vaccination trials.
authors.affiliation: Medical Oncology, Department of Internal Medicine, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland.
authors.forename: Senta M
authors.initials: SM
authors.lastname: Walton
authors.forename: Marco
authors.initials: M
authors.lastname: Gerlinger
authors.forename: Olga
authors.initials: O
authors.lastname: de la Rosa
authors.forename: Natko
authors.initials: N
authors.lastname: Nuber
authors.forename: Ashley
authors.initials: A
authors.lastname: Knights
authors.forename: Asma
authors.initials: A
authors.lastname: Gati
authors.forename: Monika
authors.initials: M
authors.lastname: Laumer
authors.forename: Laura
authors.initials: L
authors.lastname: Strauss
authors.forename: Carolin
authors.initials: C
authors.lastname: Exner
authors.forename: Niklaus
authors.initials: N
authors.lastname: Schäfer
authors.forename: Mirjana
authors.initials: M
authors.lastname: Urosevic
authors.forename: Reinhard
authors.initials: R
authors.lastname: Dummer
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Tiercy
authors.forename: Andreas
authors.initials: A
authors.lastname: Mackensen
authors.forename: Elke
authors.initials: E
authors.lastname: Jaeger
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lévy
authors.forename: Alexander
authors.initials: A
authors.lastname: Knuth
authors.forename: Dirk
authors.initials: D
authors.lastname: Jäger
authors.forename: Alfred
authors.initials: A
authors.lastname: Zippelius
mesh_terms: D017951:Antigen Presentation / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology*; D015153:Blotting, Western; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D018984:Epitopes, T-Lymphocyte / Q000276:immunology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D008545:Melanoma / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D020691:rab GTP-Binding Proteins / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; C412058:RAB38 protein, human; D020691:rab GTP-Binding Proteins