Théry Clotilde, Duban Livine, Segura Elodie, Véron Philippe, Lantz Olivier, Amigorena Sebastian
INSERM U520, Institut Curie, 12 rue Lhomond, 75005 Paris, France.
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.
树突状细胞（DCs）分泌源自内体的囊泡，称为外泌体，其携带主要组织相容性复合体（MHC）和T细胞共刺激分子。在此，我们发现注射携带抗原或肽的外泌体可在体内诱导抗原特异性初始CD4 + T细胞活化。在体外，外泌体不会诱导抗原依赖性T细胞刺激，除非培养物中也存在成熟的CD8α-DCs。这些成熟的DCs可能为II类MHC阴性，但必须携带CD80和CD86。因此，外泌体除了携带抗原外，还促进DCs之间功能性肽-MHC复合物的交换。这种机制可能会增加携带特定肽的DCs数量，从而放大初次适应性免疫反应的启动。
