| Overwhelming evidences demonstrated that dendritic cells (DCs),the most potent professional antigen presenting cells (APC) which expressed high levels of MHC class I and II and costimula;ory molecules, were efficient in phagocytosing antigens ,migrating to lymphoid organs ,and presenting antigens to naive T cells.The unique ability of DCs to induce and sustain primary immune responses made them optima candidates for vadccination protocols in cancer immunomerapy.DCs played an important role in initiating innate and adaptive immune responses, especially the potent antitumor immunity .Immature DCs had specialized antigen uptake and processing machineries, whereas mature DCs had an extraordinary capacity to present antigens and stimulate nai've T cells .Functionally, mature DCs were 100 times more tumor associated antigen (TAA) could induce protective/rejection immune responses in animal models and promising preliminary data are reported in human .Several systems had been used to deliver TAA to DCs, including 1) defined peptides of known sequences ; 2) undefined acideluted peptides from autologous tumors; 3) whole tumor lysates; 4) retroviral and adenoviral vectors; 5) tumor cell-derived RNA; 6) fusion of DCs with tumor cells and (or) exosomes derived from DCs pulsed with tumor peptides (subcellular structures containing high levels of MHC molecules and peptides). Recently, apoptotic tumor cells were shown to be efficiently phagocytosed by immature DCs . Phagocytosis of apoptotic cells by immature DCs was an active, receptormediated process, which involved CD36 and the integrin receptor or a expressing in immature DCs. Then DCs processed, cross-presented tumor Ag from tumor apoptotic cells and stimulated antigen-specific CD8+ CTL. The utilization of apoptotic tumor cells as tumor antigens raised the possibility that DCs elicited the antitumor specific CTL responses without identification of tumor associated antigen (TAA) or tumor specific antigen (TSA).Objective: To observe the activation effect on T lymphocyte by cord blood-derived dendritic cells(DCs) loading with apoptotic HO-8910 tumor cells, and the killing rates of tumor specific cyto toxic T lymphocyte (CTL) on ovarian cancer cells in vitor .To find the optimal means loading cord blood derived DCs for inducing high effective immunity against ovarian cancer ,to set the base for future animal experiment and clinical trial ,and to give an new approach in the biological treatment of ovarian carcinoma.Methods: Cord billd was collected from healthy term delivery mother. Cord blood mononuclear cells(CBMNCs) were separated by density gradient centrifugation(Ficoll-Hypaque).The adherent fraction of CBMNCs was cultured with the presence of felevant cytokines (rhGM-CSF 2000u/ml, rhIL-4 500u/ml and rhTNF-al00u/ml) to generate DCs. The tumor cells of human ovarian cancer cell line HO-8910 were induced apoptosis with 0.5mg DDP /107cell/ml for 3-4h .The early cells apoptotic rate was defined by FITC-labeled annexin VVpropidium iodide:PI)- staining by FCM. Early apoptotic tumor cells were used to pulse DCs ,as tumor antigens .they primed DCs in vitro. The ability of DCs stimulating T lymphocyte proliferation was observed by mixed T lymphocyte reaction using 3H-TdR incorporation .MTT assay was employed to test the inhibition rates of tumor specific cytotoxic T lymphocyte on HO-8910 ovarian cancer cells. Md prepare AP-DC vaccines.and these vaccines were applied to immunize mice .Changes of the tumor size and mice life-span were recorded .Results: DCs with typical morphology and phenotype were harvested from the adherent fraction of CBMNCs with the presence of rhGM-CSF2000u/ml, rhIL-4500u/ml and rliTNF-a l00u/ml in vitro. HO-8910 rumor cells induced apoptosis with 05mg DDP /107cell/ml for 3-4h . Loading this tumor antigen, DCs were able to stimulate the amplification of allogeneic mixed T lymphocytes .The simulate index (SI) of the loading groups are higher than the unloading group at effector : target ratios of 1:10 ,1:50 and 1:100. The killing rales of the loa...
|
PDF Full Text Request