title: Malignant effusions and immunogenic tumour-derived exosomes.
abstract: BACKGROUND
  Exosomes derived from tumours are small vesicles released in vitro by tumour cell lines in culture supernatants. To assess the role of these exosomes in vivo, we examined malignant effusions for their presence. We also investigated whether these exosomes could induce production of tumour-specific T cells when pulsed with dendritic cells.
  
  
  METHODS
  We isolated exosomes by ultracentrifugation on sucrose and D(2)O gradients of 11 malignant effusions. We characterised exosomes with Western blot analyses, immunoelectron microscopy, and in-vitro stimulations of autologous T lymphocytes.
  
  
  RESULTS
  Malignant effusions accumulate high numbers of membrane vesicles that have a mean diameter of 80 nm (SD 30). These vesicles have antigen-presenting molecules (MHC class-I heat-shock proteins), tetraspanins (CD81), and tumour antigens (Her2/Neu, Mart1, TRP, gp100). These criteria, including their morphological characteristics, indicate the similarities between these vesicles and exosomes. Exosomes from patients with melanoma deliver Mart1 tumour antigens to dendritic cells derived from monocytes (MD-DCs) for cross presentation to clones of cytotoxic T lymphocytes specific to Mart1. In seven of nine patients with cancer, lymphocytes specific to the tumour could be efficiently expanded from peripheral blood cells by pulsing autologous MD-DCs with autologous ascitis exosomes. In one patient tested, we successfully expanded a restricted T-cell repertoire, which could not be recovered carcinomatosis nodules.
  
  
  CONCLUSIONS
  Exosomes derived from tumours accumulate in ascites from patients with cancer. Ascitis exosomes are a natural and new source of tumour-rejection antigens, opening up new avenues for immunisation against cancers.
authors.affiliation: Departments of Clinical Biology, Immunology Unit, Institut Gustave Roussy, Villejuif, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Andre
authors.forename: Noel E C
authors.initials: NE
authors.lastname: Schartz
authors.forename: Mojgan
authors.initials: M
authors.lastname: Movassagh
authors.forename: Caroline
authors.initials: C
authors.lastname: Flament
authors.forename: Patricia
authors.initials: P
authors.lastname: Pautier
authors.forename: Philippe
authors.initials: P
authors.lastname: Morice
authors.forename: Christophe
authors.initials: C
authors.lastname: Pomel
authors.forename: Catherine
authors.initials: C
authors.lastname: Lhomme
authors.forename: Bernard
authors.initials: B
authors.lastname: Escudier
authors.forename: Thierry
authors.initials: T
authors.lastname: Le Chevalier
authors.forename: Thomas
authors.initials: T
authors.lastname: Tursz
authors.forename: Sebastian
authors.initials: S
authors.lastname: Amigorena
authors.forename: Graca
authors.initials: G
authors.lastname: Raposo
authors.forename: Eric
authors.initials: E
authors.lastname: Angevin
authors.forename: Laurence
authors.initials: L
authors.lastname: Zitvogel
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000276:immunology / Q000302:isolation & purification*; D002277:Carcinoma / Q000276:immunology*; D022162:Cytoplasmic Vesicles / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D005260:Female; D006801:Humans; D058965:MART-1 Antigen; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000302:isolation & purification; D016066:Pleural Effusion, Malignant / Q000166:cytology / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D058965:MART-1 Antigen; C548667:MLANA protein, human; D009363:Neoplasm Proteins