|
|
|
|
|
|
|
||
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
© The Rockefeller University Press,
0021-9525/1999//599 $5.00
The Journal of Cell Biology, Volume 147, Number 3,
, 1999 599-610
Original Article |
Molecular Characterization of Dendritic Cell-Derived Exosomes
: Selective Accumulation of the Heat Shock Protein Hsc73
b Commissariat à L'Energie Atomique, Laboratoire de Chimie des Protéines, 38054 Grenoble Cedex, France
c Centre National de la Recherche Scientifique URA 1301, Laboratoire d'Immunologie Cellulaire, Département de Biologie Clinique, Institut Gustave-Roussy, 94805 Villejuif Cedex, France
d Second University of Milan, Department of Biotechnology and Biological Sciences, 20126 Milan, Italy
e Centre National de la Recherche Scientifique UMR 144, Institut Curie, 75005 Paris, France
INSERM, U520, Institut Curie, 12 rue Lhomond, 75005 Paris, France.33-1-42-34-63-8233-1-42-34-63-89
sebastian.amigorena{at}curie.fr
Exosomes are membrane vesicles secreted by hematopoietic cells upon fusion of late multivesicular endosomes with the plasma membrane. Dendritic cell (DC)-derived exosomes induce potent antitumor immune responses in mice, resulting in the regression of established tumors (Zitvogel, L., A. Regnault, A. Lozier, J. Wolfers, C. Flament, D. Tenza, P. Ricciardi-Castagnoli, G. Raposo, and S. Amigorena. 1998. Nat. Med. 4:594–600). To unravel the molecular basis of exosome-induced immune stimulation, we now analyze the regulation of their production during DC maturation and characterize extensively their protein composition by peptide mass mapping. Exosomes contain several cytosolic proteins (including annexin II, heat shock cognate protein hsc73, and heteromeric G protein Gi2
), as well as different integral or peripherally associated membrane proteins (major histocompatiblity complex class II, Mac-1 integrin, CD9, milk fat globule-EGF-factor VIII [MFG-E8]). MFG-E8, the major exosomal component, binds integrins expressed by DCs and macrophages, suggesting that it may be involved in exosome targeting to these professional antigen-presenting cells. Another exosome component is hsc73, a cytosolic heat shock protein (hsp) also present in DC endocytic compartments. hsc73 was shown to induce antitumor immune responses in vivo, and therefore could be involved in the exosome's potent antitumor effects. Finally, exosome production is downregulated upon DC maturation, indicating that in vivo, exosomes are produced by immature DCs in peripheral tissues. Thus, DC-derived exosomes accumulate a defined subset of cellular proteins reflecting their endosomal biogenesis and accounting for their biological function.
Key Words: endosomes • antigen presentation • dendritic cells • exosomes • heat shock protein
© 1999 The Rockefeller University Press
1.used in this paper: AEP, acid-eluted peptide; APC, antigen-presenting cell; B-EBV, Epstein-Barr virus–transformed B lymphocyte; BM, bone marrow; CLAP, chymostatin, leupeptin, aprotinin, pepstatin; DC, dendritic cell; FFE, free-flow electrophoresis; gp, glycoprotein; HDM, high density membrane; hsp, heat shock protein; Ii, invariant chain; LDM, low density membrane; LPS, lipopolysaccharide; MALDI-TOF-MS, matrix-assisted laser desorption ionization–time of flight mass spectrometry; MFG-E8, milk fat globule-EGF-factor VIII; MHC, major histocompatibility complex; MVB, multivesicular body; TEA, triethanolamine-acetic acid-EDTA; TfR, transferrin receptor
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
Related Article
|
|
