Indirect activation of naïve CD4+ T cells by dendritic cell-derived exosomes

Nat Immunol. 2002 Dec;3(12):1156-62. doi: 10.1038/ni854. Epub 2002 Nov 11.


Dendritic 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 CD8alpha- 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen Presentation
  • Antigens, CD / immunology
  • B7-1 Antigen / immunology
  • B7-2 Antigen
  • CD4-Positive T-Lymphocytes / immunology*
  • Cell Communication / immunology
  • Dendritic Cells / immunology*
  • Dendritic Cells / ultrastructure
  • Flow Cytometry
  • Histocompatibility Antigens Class II / immunology
  • Lymphocyte Activation* / immunology
  • Membrane Glycoproteins / immunology
  • Mice
  • Secretory Vesicles / immunology


  • Antigens, CD
  • B7-1 Antigen
  • B7-2 Antigen
  • Cd86 protein, mouse
  • Histocompatibility Antigens Class II
  • Membrane Glycoproteins