Van Niel G, Mallegol J, Bevilacqua C, Candalh C, Brugière S, Tomaskovic-Crook E, Heath J K, Cerf-Bensussan N, Heyman M
INSERM EMI 0212, Faculté Necker-Enfants Malades, 156 rue de Vaugirard, Paris, France.
Gut. 2003 Dec;52(12):1690-7. doi: 10.1136/gut.52.12.1690.
Intestinal epithelial cells secrete exosome-like vesicles. The aim of this study was to characterise murine intestinal epithelial exosomes and to analyse their capacity to inform the immune system in vivo in mice.
Epithelial exosomes were obtained from the murine epithelial cell line MODE K incubated in the presence or absence of interferon gamma (IFN-gamma) together with pepsin/trypsin ovalbumin hydrolysate (hOVA) to mimic luminal digestion. Exosomes isolated from MODE K conditioned media (EXO-hOVA and EXO-hOVA-IFN) were characterised by western blot, peptide mapping, and mass spectrometry. They were injected intraperitoneally to C3H/HeN mice to test their immunocompetence.
MODE K epithelial exosomes displayed major histocompatibility complex (MHC) class I and class II (upregulated by IFN-gamma) molecules and tetraspan proteins (CD9, CD81, CD82) potentially involved in the binding to target cells. A33 antigen, an Ig-like molecule highly specific for intestinal epithelial cells, was enriched in exosomes and was also found in mice mesenteric lymph nodes, suggesting exosome migration towards the gut associated lymphoid tissues. Intraperitoneal injection of EXO-hOVA or EXO-hOVA-IFN did not induce humoral or cellular tolerance to OVA in mice. In contrast, exosomes obtained after incubation with IFN-gamma (EXO-hOVA-IFN), bearing abundant MHC class II/OVA complexes, induced a specific humoral immune response.
Epithelial exosomes are antigen presenting vesicles bearing MHC class II/peptide complexes that prime for an immunogenic rather than tolerogenic response in the context of a systemic challenge. In the intestine, both the mucosal microenvironment and local effector cells are probably key players in determining the outcome of the immune response to exosome derived epitopes.
肠道上皮细胞分泌外泌体样囊泡。本研究的目的是对小鼠肠道上皮外泌体进行表征，并分析其在小鼠体内影响免疫系统的能力。
上皮外泌体从在有或无干扰素γ（IFN-γ）存在的情况下培养的小鼠上皮细胞系MODE K中获得，同时加入胃蛋白酶/胰蛋白酶卵清蛋白水解物（hOVA）以模拟腔内消化。从MODE K条件培养基中分离的外泌体（EXO-hOVA和EXO-hOVA-IFN）通过蛋白质印迹、肽图谱分析和质谱进行表征。将它们腹腔注射到C3H/HeN小鼠体内以测试其免疫活性。
MODE K上皮外泌体展示了主要组织相容性复合体（MHC）I类和II类（由IFN-γ上调）分子以及可能参与与靶细胞结合的四跨膜蛋白（CD9、CD81、CD82）。A33抗原是一种对肠道上皮细胞高度特异的免疫球蛋白样分子，在外泌体中富集，并且也在小鼠肠系膜淋巴结中发现，表明外泌体向肠道相关淋巴组织迁移。腹腔注射EXO-hOVA或EXO-hOVA-IFN未在小鼠中诱导对OVA的体液或细胞耐受。相反，与IFN-γ孵育后获得的外泌体（EXO-hOVA-IFN）携带丰富的MHC II类/OVA复合物，诱导了特异性体液免疫反应。
上皮外泌体是携带MHC II类/肽复合物的抗原呈递囊泡，在全身刺激的情况下引发免疫原性而非耐受性反应。在肠道中，黏膜微环境和局部效应细胞可能是决定对外泌体衍生表位免疫反应结果的关键因素。
