【摘要】 目的探讨脐血树突状细胞(UBDC)及其分泌的亚细胞结构外来体(exosomes)的特性,以及他们对细胞毒性T细胞(CTL)杀伤活性的增强作用。方法分离脐血单个核细胞(UBMC),用rhSCF、rhGM-CSF及rhIL-4诱导12d,加入经反复冻融提取的肿瘤细胞膜抗原,继续培养2d。收集DC并从其培养上清中通过离心(1×105g)分离外来体。用流式细胞术、SDS-PAGE、透射电子显微镜(TEM)和MTT比色法,对DC和外来体的特性及其对CTL杀伤活性的增强作用进行分析。结果用3种细胞因子体外诱导UBMC12d,可使其扩增10倍,并出现DC典型的形态特征。负载肿瘤抗原后,细胞表面可高表达MHC-I、MHC-II、CD40、CD80、CD86、CD11c和CD54。利用超速离心法能从DC培养上清中分离出外来体。混合淋巴细胞反应(MLR)和CTL杀伤活性的分析表明,脐血DC分泌的外来体能有效地刺激T细胞增殖并增强CTL的杀伤活性。结论由UBMC可诱导出大量的DC并分泌外来体。后者可有效地向CTL细胞递呈肿瘤抗原使之活化并增强其杀伤活性。更多还原

【Abstract】 AIM: To investigate the properties of exosomes secreted by dendritic cells(DCs) derived from human umbilical cord blood mononuclear cells(HUBMCs)and its enhancement of CTL cytotoxicity. METHODS: The HUBMCs were separated from human umbilical cord blood(HUCB).The generation of DCs were induced for 12 days in medium containing SCF, IL-4 and GM-CSF. Tumor antigen extracted by repeated freeze-thawing were added to culture medium and cultured successively for 2 days. The DCs were collected and exosomes were separated from culture supernatant through centrifugation at 100 000 g. The exosomes-associated properties were analyzed by FCM, SDS-PAGE, transmission electron microscope(TEM)and MTT colorimetry. RESULTS: After being induced for 12 days with SCF, IL-4 and GM-CSF the number of DCs had a 10-fold increase and displayed typically morphological characteristics of DCs. FCM analysis showed that the DCs loaded with tumor antigen expressed highly MHC-I, MHC-II, CD40, CD80, CD86, CD11c and CD54. Exosomes could be separated from culture supernatant of DCs by ultracentrifugation. Mixed lymphocyte reation(MLR) and cytotoxicity assay showed that exosomes secreted by DCs could effectively stimulate T cell proliferation and enhance their cytotoxicity. CONCLUSION: A large number of DCs are obtained from UBMCs and the exosomes are secreted from them in vitro. The exosomes can present tumor antigen to T cells and enhance the cytotoxicity of CTLs.[更多还原