Establishment of dendritic cell immunotherapy based on the chemokine expression profile of cancer cells

点击翻译按钮获取中文摘要

Some previous reports indicated that fusion cells of DCs and tumor cells could function as antigen-presenting cells(APCs) containing tumor specific antigens. Several clinical trials with DC/Tumor fusion cells demonstrated an obvious tumor regression in patients with advanced stage of disease. In our study, the DCs and irradiated tumor cells were mixed at a ratio of 1:1 and incubated in serum-free RPMI 1640 medium containing 50% polyethylene glycol(PEG) for 1 min to induce cell fusion. Then, we used electrofusion techniques for producing the fusion cells. In a preliminary study, the optimal cell numbers (1.0x10^6 of DCs : 1.0x 10^6 of tumor cells/mL) and alignment voltage (100V for 10sec) were determined. Cell fusion was performed using ECM2001 electrofusion apparatus and confirmed by fluorescent microscopy and flow cytometry. The DCs were successfully fused with the allogeneic gastric cancer cells resulting in hybrid cells that functioned as antigen-presenting cells, because they induced allogeneic CD4+ T cell proliferation. A gastric cancer cell line, MKN-45, and DC hybrid cell induced autologous CD4+ and CD8+ T cell proliferation, indicating that MKN-45-DC hybrids present some antigens from the MKN-45 cells to the CD4+ and CD8+ T cells. CD8+ T cells stimulated by the MKN-45-DC hybrid cells were able to kill MKN-45 when used for immunization. The CTLs killed another gastric cancer cell line, MKN-1, as well as a melanoma cell line, 888 mel, suggesting the recognition of a shared tumor antigen. MKN-45 specific CTLs can recognize carcinoembryonic antigen(CEA), indicating that the killing is due to tumor antigens as well as alloantigens. Further studies are requested for practical use of DC/tumor fusion cells in cancer therapy. Moreover, the mechanisms of counterattack by tumor cells against immune cells should be clarified to establish an effective DC treatment for cancer.