Expression hierarchy of T cell epitopes from melanoma differentiation antigens: unexpected high level presentation of tyrosinase-HLA-A2 Complexes revealed by peptide-specific, MHC-restricted, TCR-like antibodies.
Peptide Ags presented by class I MHC molecules on human melanomas and that are recognized by CD8(+) T cells are the subjects of many studies of antitumor immunity and represent attractive candidates for therapeutic approaches. However, no direct quantitative measurements exist to reveal their expression hierarchy on the cell surface. Using novel recombinant Abs which bind these Ags with a peptide-specific, MHC-restricted manner, we demonstrate a defined pattern of expression hierarchy of peptide-HLA-A2 complexes derived from three major differentiation Ags: gp100, Melan-A/Mart-1, and tyrosinase. Studying melanoma cell lines derived from multiple patients, we reveal a surprisingly high level of presentation of tyrosinase-derived complexes and moderate to very low expression of complexes derived from other Ags. No correlation between Ag presentation and mRNA expression was found; however, protein stability may play a major role. These results provide new insights into the characteristics of Ag presentation and are particularly important when such targets are being considered for immunotherapy. These results may shed new light on relationships between Ag presentation and immune response to cancer Ags.
Faculty of Biology, Technion-Israel Institute of Technology, Haifa, Israel.
Yael
Y
Michaeli
Galit
G
Denkberg
Keren
K
Sinik
Liz
L
Lantzy
Chiang
C
Chih-Sheng
Celine
C
Beauverd
Tamar
T
Ziv
Pedro
P
Romero
Yoram
Y
Reiter
D017951:Antigen Presentation / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D015789:HLA-A2 Antigen / Q000276:immunology*; D006801:Humans; D058965:MART-1 Antigen; D008545:Melanoma / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology; D014442:Monophenol Monooxygenase / Q000276:immunology*; D009363:Neoplasm Proteins / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D058951:gp100 Melanoma Antigen
D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D058965:MART-1 Antigen; C548667:MLANA protein, human; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C548637:PMEL protein, human; D012333:RNA, Messenger; D058951:gp100 Melanoma Antigen; D014442:Monophenol Monooxygenase