[Experimental study on the immune response of fusion tumor vaccine of HepG2 and dendritic cells in vitro].

ABSTRACT

Objective: To estimate the immune response of HepG2/dendritic cell (DC) fusion cells vaccines against HepG2 cells in vitro. Methods: Peripheral blood mononuclear cells (PBMCs) were isolated from healthy donors by Ficoll-Hypaque density-gradient centrifugation.Then DC were obtain from PBMCs by culturing in medium containing granulocyte macrophage colony-stimulating factor (GM-CSF) and interleukin-4 (IL-4) for 5 days.DC and HepG2 fusion cells were induced by polythyleneglycol (PEG). The fusion cells were examined under fluorescence microscope by labeling DCs and HepG2 with green and red fluorescein, respectively, and then the fusion rates were analyzed by flow cytometry.The capacity of fusion cells to secrete interleukin (IL)-12 and stimulate the proliferation of T lymphocyte was assessed by ELISA and Flow cytometry, respectively.ELISPOT was used to assess the interferon gamma (IFN-γ) produced by cytotoxicity T lymphocyte (CTL), and the specific killing ability of fusion cells induce-CTL targeting HepG2 was estimated. Results: The fusion rate of HepG2/DC was 54.5%, and the fusion cells expressed a higher levels of DC mature marker CD80 and costimulatory molecules CD83, CD86 and MHC-Ⅰ, MHC-Ⅱ molecules HLA-ABC and HLA-DR than those in immature DCs (P<0.01). HepG2/DC showed a greater capacity to secrete high level of IL-12 (P<0.05) and activate proliferation of lymphocytes in vitro, as compared with DCs alone and DCs mix HepG2 (P<0.01). The HepG2/DC -activated CTL generated higher IFN-γ level and had a specific killing ability against HepG2 cells at the effecter/target ratio 30∶1 (31.4%±2.4%) and 100∶1 (57.6%±7.3%) (P<0.01). Conclusions: HepG2/DC fusion cells could efficiently stimulate T lymphocytes to generate specific CTL targeting HepG2 cells.It might be a promising strategy of immunotherapy for HCC.