ICAM-1 on exosomes from mature dendritic cells is critical for efficient naive T-cell priming

摘要: 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 T-cell responses (ie, tolerance versus priming), we asked whether DC maturation also influenced the priming abilities of their exosomes. We show that exosomes by lipopolysaccharide (LPS)-treated 50- 100-fold more potent antigen-specific activation vitro than from In vitro, B lymphocytes ability prime naive T cells. vivo, only trigger effector responses, leading fast skin graft rejection. Proteomic biochemical analyses revealed enriched MHC class II, B7.2, intercellular adhesion molecule 1 (ICAM-1), bear little milk-fat globule-epidermal growth factor-factor VIII (MFG-E8) as compared with Functional analysis using DC-derived knock-out mice showed II ICAM-1 required for cells, whereas B7.2 MFG-E8 dispensable. Therefore, changes protein composition reflect signals received