人胃癌BGC823细胞RNA转染脐血树突状细胞分泌的exosomes对T细胞增殖及杀瘤活性的影响

Effect of exosomes secreted by human cord blood dendritic cells transfected with BGC823 cells RNA on proliferation and cytotoxicity of T cells

目的:探讨肿瘤细胞RNA转染脐血树突状细胞(DCs)分泌的exosomes对细胞毒T细胞(CTL)特异性抗肿瘤作用的影响。方法:分离脐血单个核细胞,经干细胞因子(SCF)、粒细胞集落刺激因子(GM-CSF)、白介素-4(IL-4)诱导和BGC823 RNA转染形成成熟DCs,收集DCs培养上清,采用超速离心法分离exosomes,并用透射电镜、SDS-PAGE和Western blot进行鉴定;利用MTT比色分析法观察exosomes诱导T细胞增殖和CTL的杀瘤活性。结果:经诱导和BGC823RNA转染后DCs分泌的exosomes表达MHC-Ⅱ、CD54、CD86,对T细胞的刺激指数(SI)为(2.53±0.09),CTL杀瘤活性(64.92±0.37)%,较转染前的(1.26±0.07)和(35.28±0.16)%均增高(P<0.01)。结论:从脐血中诱导的DCs经肿瘤细胞RNA转染后分泌的exosomes,能在体外活化T细胞,有望成为新型非细胞结构的DCs亚单位疫苗。

Aim ： To investigate the properties of exosomes secreted by dendritic cells（DCs） derived from human cord blood mononuclear cells（CBMCs） and its affection on CTL cytotoxicity. Methods：The CBMCs were separated from human cord blood. The generation of mature cord blood DCs（CBDC） were induced in medium containing SCF,IL-4 and GM-CSF and transfected BGC823 cells total RNA. The exosomes separated from culture supernatant of mature CBDC through centrifugation were analyzed by transmission electron microscope （ TEM ） , SDS-PAGE, western blot and MTT colorimetry. Resuits： The exosomes derived from mature CBDCs displayed typically morphological characteristics and expressed MHC-Ⅱ ,CD54, CD86. The stimulate index to T cells （SI） was 2.53 ± 0.09 and the activity of CTL was （64.92 ± 0.37） % , which were both higher than 1.26 ± 0.07 and （35.28 ± 0. 16）% before DCs transfected. Conclusion： The exosomes derived from CBDCs ean activate T cell in vitro,and may be developed into a new DCs aeellular subunit vaccine.