Spontaneous CD8 T cell responses against the melanocyte differentiation antigen RAB38/NY-MEL-1 in melanoma patients.
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.
Walton
Senta M
SM
Medical Oncology, Department of Internal Medicine, University Hospital Zurich, Raemistrasse 100, CH-8091 Zurich, Switzerland.
Gerlinger
Marco
M
de la Rosa
Olga
O
Nuber
Natko
N
Knights
Ashley
A
Gati
Asma
A
Laumer
Monika
M
Strauss
Laura
L
Exner
Carolin
C
Schäfer
Niklaus
N
Urosevic
Mirjana
M
Dummer
Reinhard
R
Tiercy
Jean-Marie
JM
Mackensen
Andreas
A
Jaeger
Elke
E
Lévy
Frédéric
F
Knuth
Alexander
A
Jäger
Dirk
D
Zippelius
Alfred
A
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*
D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; C412058:RAB38 protein, human; D020691:rab GTP-Binding Proteins