免疫共刺激分子增强自噬小体疫苗诱导的T细胞应答

Costimulate moleculars amplified the DRibble mediated T cells response

自噬小体疫苗DRibble被证实可以有效诱导小鼠和人T细胞应答,为了进一步增强DRibble疫苗诱导人T细胞应答的能力,本研究将免疫共刺激分子OX40、CD80和对照质粒分别转染至表达CMV pp65蛋白的LT3-pp65细胞系中,制备3种类型的DRibble疫苗为:Ctrl/pp65 DRibble、OX40/pp65 DRibble和CD80/pp65 DRibble。通过ELISA法检测不同DRibble疫苗诱导树突状细胞表达IL-12的水平,结果显示,OX40/pp65 DRibble和CD80/pp65 DRibble诱导树突状细胞表达IL-12的水平显著高于Ctrl/pp65 DRibble。进一步将3种DRibble疫苗分别刺激树突状细胞后与扩增的CMV特异性T细胞共培养,通过流式细胞术检测表达IFN-γ的T细胞占总T细胞的百分比。实验结果显示,与Ctrl/pp65 DRibble相比,OX40/pp65DRibble和CD80/pp65 DRibble诱导CD8+T细胞表达IFN-γ的能力显著增高,OX40/pp65 DRibble和CD80/pp65 DRibble诱导CD4^+T细胞表达IFN-γ的水平也显著高于Ctrl/pp65 DRibble。实验证明免疫共刺激分子OX40和CD80修饰均可以加强DRibble疫苗体外诱导人T细胞应答的能力。

Autophagosomes derived from tumor cells have been proved to induce potent T cell response both in mouse and human. In human in vitro study, dendritic cells（DC）loaded with cytomegalovirus（CMV）pp65 antigen-containing DRibble were capable to efficiently re-stimulate pp65-specific T-cell recall responses from freshly isolated or frozen humanperipheral blood mononuclear cell（PBMC）. This study developed more robust assays using in vitro expanded antigen-specific T cells that contained a much higher percentage of antigen-specific T cells. DC cross-presentation efficiency of OX40 and CD80 modified pp65-DRibble was detected by intracellular IFN-γ staining. Compared with Ctrl/pp65 DRibble, the percentage of IFN-γ＋ in total CD8＋ T cells andCD4＋ T cells was improvedwith OX40/pp65 DRibbleand CD80/pp65 DRibble stimulation. In addition, vaccine induced IL-12indendritic cells, whichpolarizes Th cells toward the IFN-γ high Th1 phenotype, evaluated by ELISA inco-culture supernatantwas dramatically higher in OX40/pp65 DRibble and CD80/pp65 DRibblegroups than in Ctrl/pp65 DRibble group. These results have implications for the immuneactivity of OX40 and CD80 modified DRibble and choice for prospective clinical use ofDRibble-based cancer immunotherapy.