Nature Immunology
3, 1156 - 1162 (2002)
Published online: 11 November 2002; | doi:10.1038/ni854
Indirect activation of naïve CD4+ T cells by dendritic cell−derived exosomesClotilde Théry1, 3, Livine Duban1, 2, 3, Elodie Segura1, Philippe Véron1, Olivier Lantz1, 2, 3
& Sebastian Amigorena1, 31
INSERM U520, Institut Curie, 12 rue Lhomond, 75005 Paris, France. 2
Laboratoire d'Immunologie Préclinique, Institut Curie, 26 rue d'Ulm, 75005 Paris, France. 3
These authors contributed equally to this work.
Correspondence should be addressed to Sebastian Amigorena sebastian.amigorena@curie.frDendritic cells (DCs) secrete vesicles of endosomal origin, called exosomes, that bear major histocompatibility complex (MHC) and T cell costimulatory molecules. Here, we found that injection of antigen- or peptide-bearing exosomes induced antigen-specific naïve CD4+ T cell activation in vivo. In vitro, exosomes did not induce antigen-dependent T cell stimulation unless mature CD8 - DCs were also present in the cultures. These mature DCs could be MHC class II−negative, but had to bear CD80 and CD86. Therefore, in addition to carrying antigen, exosomes promote the exchange of functional peptide-MHC complexes between DCs. Such a mechanism may increase the number of DCs bearing a particular peptide, thus amplifying the initiation of primary adaptive immune responses.
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