The production of a new MAGE-3 peptide presented to cytolytic T lymphocytes by HLA-B40 requires the immunoproteasome.
By stimulating human CD8(+) T lymphocytes with autologous dendritic cells infected with an adenovirus encoding MAGE-3, we obtained a cytotoxic T lymphocyte (CTL) clone that recognized a new MAGE-3 antigenic peptide, AELVHFLLL, which is presented by HLA-B40. This peptide is also encoded by MAGE-12. The CTL clone recognized MAGE-3--expressing tumor cells only when they were first treated with IFN-gamma. Since this treatment is known to induce the exchange of the three catalytic subunits of the proteasome to form the immunoproteasome, this result suggested that the processing of this MAGE-3 peptide required the immunoproteasome. Transfection experiments showed that the substitution of beta5i (LMP7) for beta5 is necessary and sufficient for producing the peptide, whereas a mutated form of beta5i (LMP7) lacking the catalytically active site was ineffective. Mass spectrometric analyses of in vitro digestions of a long precursor peptide with either proteasome type showed that the immunoproteasome produced the antigenic peptide more efficiently, whereas the standard proteasome more efficiently introduced cleavages destroying the antigenic peptide. This is the first example of a tumor-specific antigen exclusively presented by tumor cells expressing the immunoproteasome.
Schultz
Erwin S
ES
Cellular Genetics Unit, Ludwig Institute for Cancer Research, Université de Louvain, 74 Ave., Hippocrate UCL 74.59, B-1200 Brussels, Belgium.
Chapiro
Jacques
J
Lurquin
Christophe
C
Claverol
Stéphane
S
Burlet-Schiltz
Odile
O
Warnier
Guy
G
Russo
Vincenzo
V
Morel
Sandra
S
Lévy
Frédéric
F
Boon
Thierry
T
Van den Eynde
Benoît J
BJ
van der Bruggen
Pierre
P
D000256:Adenoviridae / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D019556:COS Cells; D002999:Clone Cells / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000378:metabolism*; D016207:Cytokines / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology; D015235:HLA-B Antigens / Q000276:immunology*; D059947:HLA-B40 Antigen; D006801:Humans; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits; D013602:T-Lymphocytes, Cytotoxic / Q000201:enzymology* / Q000276:immunology* / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D016207:Cytokines; D015235:HLA-B Antigens; D059947:HLA-B40 Antigen; C072013:MAGEA3 protein, human; D009097:Multienzyme Complexes; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D021122:Protein Subunits; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex