Antitumor effect of immunization with fusion of dendritic cells and hepatocellular carcinoma cells in mice

BACKGROUND: Important advances have made within the past few years in the treatment of hepatocellular carci- noma (HCC), however, the long-term prognosis after re- section of HCC remains unsatisfactory as a result of a high incidence of recurrence. This study was to investigate im- munization with fusions of DCs and HCC cells against HCC tumors transplanted to mice. METHODS: Fusion cells of dendritic cells (DCs) and H22 cells were prepared with polyethylene glycol. Expression of MHC and costimulatory molecules by dendritomas were determined by FACs. To study the antitumor immune pre- ventitive and therapeutic effects, fusions were subcuta- neously injected into naive or tumor-bearing mice; the CTL activity was assumed by the LDH method, and the ex- pression of tumour necrosis factor-α (TNF-α) and interfe- ron-γ (IFN-γ) in tumors were assayed by reverse transcrip- tion-polymerase chain reaction (RT-PCR). RESULTS: The hybridomas of DCs and H22 cells acquired both DCs and H22 cells phenotypes. Immunization of BALB/C mice with DC/H22 fusions induced protective immunity against a high dose of H22 tumor challenge. Af- ter treatment with hybridomas, the survival time of tumor- bearing mice was extended. The expression level of TNF-α and IFN-γ mRNA was markedly increased. CONCLUSION: The hybridomas of DCs and H22 cells could induce effective antitumor immune responses and may be potentially used in prevention and management of recurrence and metastasis of HCC.