title: BCR-bound antigen is targeted to exosomes in human follicular lymphoma B-cells.
abstract: BACKGROUND
  Exosomes are small membrane vesicles secreted by several cell types during exocytic fusion of multivesicular bodies with the plasma membrane. Exosomes from tumour cells can transfer antigens from cell to cell, a property favouring antigen-specific immune responses in vitro and in vivo, and are thus an interesting putative therapeutic tool in human cancers. Exosomes have been well studied in EBV (Epstein-Barr virus)-transformed human B-cell lines; however, biological stimuli regulating exosome secretion quantitatively and/or qualitatively still remain poorly defined.
  
  
  RESULTS
  We analysed the effect of the BCR stimulation on exosome release in the human follicular lymphoma B-cell line DOHH2. We found that BCR (B-cell receptor) triggering of DOHH2 cells induced the polarization of CD63(+) MHC class II compartments. Moreover, BCR stimulation increased the release of exosome-associated proteins in the extracellular space. Finally, we found that the BCR was expressed at the surface of exosomes, and could target a bound anti-human IgG to these vesicles.
  
  
  CONCLUSIONS
  BCR can modulate the protein content of exosomes upon stimulation, and can target its bound antigen to these vesicles.
authors: INSERM U520, Institut Curie, 26, rue d'Ulm, 75 248 Paris cedex 05, France.
authors: Pascale
authors: P
authors: Rialland
authors: Danielle
authors: D
authors: Lankar
authors: Graça
authors: G
authors: Raposo
authors: Christian
authors: C
authors: Bonnerot
authors: Pascale
authors: P
authors: Hubert