OBJECTIVETo investigate whether dendritic cells fused with tumor cells could elicit in vitro antitumor responses against renal cell carcinoma (RCC) cells.

METHODSRenal carcinoma cells were purified from tumor tissue excised from patients with metastatic RCC through tumor cell purifying technique and cultured in RPMI-1640 medium containing 10% FCS. Monocyte-derived DCs generated from peripheral blood mononuclear cell of RCC patients were cultured in the presence of human recombinant granulocyte-macrophage colony stimulating factor and interleukin-4. Tumor cells and DCs were cocultured in the presence of polyethylene glycol (PEG) to generate cell fusion. The phenotype of tumor cells, DCs and fusion cells were detected by flow cytometry. MTT was used to measure the ability of fusion cells to stimulate T cell proliferation. T cell-mediated antitumor responses were measured by lactate dehydrogenase release (LDH) assay for lysis of autologous tumor cells.

RESULTSThe DCs expressed MHC class I, MHC class II and costimulatary molecules (CD80 and CD86), while the renal carcinoma cells expressed a high molecular glycoprotein MUC-1. The DC/tumor fusion cells coexpressed MUC-1 and the phenotype of DCs, and could stimulate T cell proliferation effectively. CTLs stimulated by the fusion vaccine showed distinct lytie activity in vitro to autologous tumor cells.

CONCLUSIONDendritic cells fused with tumor cells can elicit distinct antitumor responses in vitro against tumor cells from patients with metastatic RCC, providing a basis for further research on the clinical application of fusion vaccine in treatment for renal cancers.