To study the endocytic activity of dendritic cells(DCs)by obtaining fusion protein HSP70-EGFP as exogenous antigen and loading it with DCs derived from human peripheral blood.Fusion protein HSP70-EGFP was prokaryotica...To study the endocytic activity of dendritic cells(DCs)by obtaining fusion protein HSP70-EGFP as exogenous antigen and loading it with DCs derived from human peripheral blood.Fusion protein HSP70-EGFP was prokaryotically expressed,isolated and purified.DCs were isolated and cultured from human peripheral blood.The DCs were divided into 3 groups in the endocytic experiment.There were 106 DCs in each group.Group 1 and 2 were respectively incubated for 30 min.with HSP70-EGFP and EGFP.Group 3 was incubated with HSP70 for 30 min,and then incubated for 30 min.with HSP70-EGFP.Subsequently,3 groups were placed in an incubator at 37℃for 0.5,1,2 and 24 h.Flow cytometry(FCM)was adopted to detect the amount of DCs with EGFP inside.IL-12 Eli-spot was adopted to detect the amount of DCs which secreted IL-12.There were 5 types in the experiment:LPS,inactive LPS,HSP70-EGFP,EGFP and no antigen.Fusion protein HSP70-EGFP was successfully obtained and its molecular weight was 97000.It accounted for 35.32%of the total protein.Under irradiation of an ultraviolet lamp,the protein solution sent out viridescent fluorescence.The result detected by FCM indicated that after incubation for 0.5 h at 37℃,the positive rate in group 1 was 63%,while the other 2 groups were negative.After incubation for 1,2 and 24 h at 37℃,the positive rates in the 3 groups were above 80%.The IL-12 Eli-spot examination shows that with HSP70-EGFP being loaded,the amount of DCs secreting IL-12 was 134.09±31.78/10^(5)cells,a little lower than that of DCs with LPS loaded(with the average point of 156.36±15.73).There was no significant difference between the 2 groups(P<0.01).By contrast,both of them were significantly higher than inactive LPS-(33.78±1.40)/10^(5)cells and EGFP-loaded(23.13±4.57)/105 cells DC groups in the amount of DCs secreting IL-12(P<0.01).The results suggest that receptor-mediated phagocytosis plays a main role in the preliminary stage of DCs internalizing HSP70-EGFP.With increasing incubation time,pinocytosis begins to dominate.HSP70-EGFP may promote DCs to secret cell factor IL-12.展开更多
基金The study was supported by the General Program of National Natural Science Foundation of China(Grant No.30400167).
文摘To study the endocytic activity of dendritic cells(DCs)by obtaining fusion protein HSP70-EGFP as exogenous antigen and loading it with DCs derived from human peripheral blood.Fusion protein HSP70-EGFP was prokaryotically expressed,isolated and purified.DCs were isolated and cultured from human peripheral blood.The DCs were divided into 3 groups in the endocytic experiment.There were 106 DCs in each group.Group 1 and 2 were respectively incubated for 30 min.with HSP70-EGFP and EGFP.Group 3 was incubated with HSP70 for 30 min,and then incubated for 30 min.with HSP70-EGFP.Subsequently,3 groups were placed in an incubator at 37℃for 0.5,1,2 and 24 h.Flow cytometry(FCM)was adopted to detect the amount of DCs with EGFP inside.IL-12 Eli-spot was adopted to detect the amount of DCs which secreted IL-12.There were 5 types in the experiment:LPS,inactive LPS,HSP70-EGFP,EGFP and no antigen.Fusion protein HSP70-EGFP was successfully obtained and its molecular weight was 97000.It accounted for 35.32%of the total protein.Under irradiation of an ultraviolet lamp,the protein solution sent out viridescent fluorescence.The result detected by FCM indicated that after incubation for 0.5 h at 37℃,the positive rate in group 1 was 63%,while the other 2 groups were negative.After incubation for 1,2 and 24 h at 37℃,the positive rates in the 3 groups were above 80%.The IL-12 Eli-spot examination shows that with HSP70-EGFP being loaded,the amount of DCs secreting IL-12 was 134.09±31.78/10^(5)cells,a little lower than that of DCs with LPS loaded(with the average point of 156.36±15.73).There was no significant difference between the 2 groups(P<0.01).By contrast,both of them were significantly higher than inactive LPS-(33.78±1.40)/10^(5)cells and EGFP-loaded(23.13±4.57)/105 cells DC groups in the amount of DCs secreting IL-12(P<0.01).The results suggest that receptor-mediated phagocytosis plays a main role in the preliminary stage of DCs internalizing HSP70-EGFP.With increasing incubation time,pinocytosis begins to dominate.HSP70-EGFP may promote DCs to secret cell factor IL-12.
