| First Author | Segura E | Year | 2005 |
| Journal | Blood | Volume | 106 |
| Issue | 1 | Pages | 216-23 |
| PubMed ID | 15790784 | Mgi Jnum | J:107454 |
| Mgi Id | MGI:3621244 | Doi | 10.1182/blood-2005-01-0220 |
| Citation | Segura E, et al. (2005) ICAM-1 on exosomes from mature dendritic cells is critical for efficient naive T-cell priming. Blood 106(1):216-23 |
| abstractText | Exosomes are secreted vesicles formed in late endocytic compartments. Immature dendritic cells (DCs) secrete exosomes, which transfer functional major histocompatibility complex (MHC)-peptide complexes to other DCs. Since immature and mature DCs induce different functional T-cell responses (ie, tolerance versus priming), we asked whether DC maturation also influenced the priming abilities of their exosomes. We show that exosomes secreted by lipopolysaccharide (LPS)-treated mature DCs are 50- to 100-fold more potent to induce antigen-specific T-cell activation in vitro than exosomes from immature DCs. In vitro, exosomes from mature DCs transfer to B lymphocytes the ability to prime naive T cells. In vivo, only mature exosomes trigger effector T-cell responses, leading to fast skin graft rejection. Proteomic and biochemical analyses revealed that mature exosomes are enriched in MHC class II, B7.2, intercellular adhesion molecule 1 (ICAM-1), and bear little milk-fat globule-epidermal growth factor-factor VIII (MFG-E8) as compared with immature exosomes. Functional analysis using DC-derived exosomes from knock-out mice showed that MHC class II and ICAM-1 are required for mature exosomes to prime naive T cells, whereas B7.2 and MFG-E8 are dispensable. Therefore, changes in protein composition and priming abilities of exosomes reflect the maturation signals received by DCs. |
