Background & objective: Dendritic cells (DCs) are the strongest antigen presenting cells (APCs). But immune therapy based on DCs for osteosarcoma has seldom been reported. This study was designed to investigate the immunologic potency and antitumor effects of fused vaccine of rat DCs on osteosarcoma.
Methods: Mononuclear cells in rat bone marrow were propagated in vitro under the condition of recombinant granulocytemacrophage colony-stimulating factor (rGM-CSF), recombinant interleukin-4 (rIL-4), and recombinant tumor necrosing factor-alpha (rTNF-alpha) to obtain DCs. DCs were purified by monoclonal antibody OX62 and magnetic beads, and confirmed by morphologic observation, phenotype determine, and functional experiments. Osteosarcoma cell line UMR-106 was fused with allogeneic or syngeneic DCs by electrofusion to produce the tumor vaccine. Each kind of tumor vaccine was injected subcutaneously into 10 rats to observe its specific antitumor effects.
Results: Survival rate of rats after injection of 1x10(7) UMR-106 cells was 70% in allogeneic tumor vaccine group, and 50% in syngeneic tumor vaccine group. The survival rats stood up to the second challenge of 1x10(7) UMR-106 cells 7 weeks after injection. After immunization of 2x10(6) UMR106-DCs, tumors in 60% of the rats bearing pre-established tumor cells diminished or vanished.
Conclusion: Fused tumor vaccine of UMR-106 cells and allogeneic DCs might induce specific anti-tumor effects on osteosarcoma.