Enhanced Anti-Tumor Immune Response Induced By MDA-MB-231(GAL+) Cells And Dendritic Cell Fusion Cells Vaccines Genetically Modified Expressing α-GAL Epitopes

Background:Fusion cell vaccines have been shown much promise,but demonstrated poor efficiency in the phase III trials.In this study,we modified MDA-MB-231(Gal+)tumor cells to expressα-1,3-galactosyltransferase(α-1,3-GT)protein and fused with dendritic cells,to potentially enhance anti-tumor effect of fusion cell vaccines in NOD-SCID mice reconstituted with a human immune system.Objective:to produce MDA-MB-231(Gal+)/DC fusion cell vaccines and study anti-tumor effect of fusion cell vaccines in viovio and viotro.Methods:MDA-MB-231 tumor cells were transfected with a reconstructed lentiviral containingα-1,3-GT genes.Western blotting analysis was used to detect the expression ofα-1,3-GT in the transfected cells.Expression ofα-Gal on the MDA-MB-231(Gal-),MDA-MB-231(Gal+)cells was measured by flow cytometry.MDA-MB-231(Gal+)/DC fusion cells were detected by fluorescence microscope.MHC-II,CD80,CD86 on the MDA-MB-231(Gal+)/DC fusion cells was detected by flow cytometry.The proliferation index of T cells stimulated by MDA-MB-231(Gal+)/DC fusion cells was measured by flow cytometry.Expression of CD25,CD69 on the T cells stimulated by MDA-MB-231(Gal+)/DC fusion cells was measured by flow cytometry.The cytotoxicity of the T cells stimulated by MDA-MB-231(Gal+)/DC fusion cells to MDA-MB-231 cells was measured by flow cytometry.Tumor growth,survival of NOD-SCID mice were observed when mice were injected with fusion cell vaccines.The levels of cytokine secretion in the serum of mice were tested by ELISA.The percentage of CD4~+T,CD8~+T cells in the peripheral blood and solid tumors were assessed by flow cytometry.Proliferation and apoptosis in MDA-MB-231 tumor xenografts were observed by immunohistochemistry.Results:MDA-MB-231(Gal+)cells could express activeα-1,3-GT and produceα-Gal in vitro.The expression of MHC-II,CD80,CD86 on the MDA-MB-231(Gal+)fusion cell vaccines were higer than other groups.The level of IL-12 secreted by the MDA-MB-231(Gal+)/DC fusion cells was higer than other groups.The proliferation index of T cells stimulated by MDA-MB-231(Gal+)/DC fusion cells was higer than other groups.The level of IL-2,IFN-γsecreted by T cells stimulated by MDA-MB-231(Gal+)/DC fusion cells was higer than other groups.T cells induced by MDA-MB-231(Gal+)/DC fusion cells showed significant cytotoxicity.Additionally,increase of INF-γ,IL-12,IL-2,total Ig G were observed in MDA-MB-231(Gal+)/DC fusion cell vaccines treated NOD-SCID mice.Furthermore,these fusion cell vaccines enhanced The percentage of CD4~+T,CD8~+T cells in the tumor and peripheral blood of immunized NOD-SCID mice.Fusion cell vaccines suppressed tumor growth and promoted apoptosis of tumor and prolonged survival in NOD-SCID mice treated MDA-MB-231(Gal+)/DC fusion cell vaccines.Conclusion:MDA-MB-231(Gal+)/DC fusion cell vaccines could enhance anti-tumor effect in NOD-SCID mice reconstituted with a human immune system.