OBJECTIVETo investigate the effects of immunization with fusions of dendritic cells and H22 cells on tumor-bearing mice and their possible mechanisms.

METHODSFusion cells of DC and H22 cells were prepared with polyethylene glycol (PEG). Expression of MHC and costimulatory molecules by dendritomas were determined by FACs. To study the antitumor immune preventative and therapeutic effects, fusions were subcutaneously injected into tumor-bearing mice. The cytotoxic T lymphocyte (CTL) activity was determined by LDH method, the expression of TNF-a and IFN-g in tumors were assayed by RT-PCR.

RESULTSThe data showed that the hybridomas of DC and H22 cells acquired both DC and H22 cell phenotypes. Immunization of BALB/C mice with DC/H22 fusions induced potent CTL activity (mean CTL activity=0.624+/-0.024, compared with DC + H22, DC, H22 groups, F = 65.46) and a protective immunity against a high dose of H22 tumor challenge. After treatment with hybridomas, the survival time of tumor-bearing mice was greatly extended (x2=18.45). The expression levels of TNF-a and IFN-g mRNA were remarkably increased (TNF-a, F = 47.84; IFN-g, F = 37.23).

CONCLUSIONSThe hybridomas of DC and H22 cells could induce effective antitumor immune responses and may have a useful potential in prevention and management of the recurrences and metastases of HCC.