title: Therapy of established tumour with a hybrid cellular vaccine generated by using granulocyte-macrophage colony-stimulating factor genetically modified dendritic cells.
abstract: Dendritic cells (DCs) are the most powerful of all antigen-presenting cells and play a critical role in the induction of primary immune responses. DC-based vaccination represents a potentially powerful strategy for cancer immunotherapy. In this study, a new approach for a DC-based melanoma vaccine was described. Splenic DCs from C57BL/6 mice were fused with B16 melanoma cells, and the resultant B16/DC hybrid cells expressed major histocompatibility complex (MHC) molecules - B7 as well as the B16 tumour marker M562 - which were enriched by Ia-mediated positive selection with a MiniMACS column. The fusion rates were 12.7-26.8%. To generate hybrid tumour vaccines with potentially greater potent therapeutic efficacy, we genetically engineered DCs with granulocyte-macrophage colony-stimulating factor (GM-CSF) prior to cell fusion. Recombinant adenovirus vector was used to mediate gene transfer into DCs with high efficiency and DCs expressed GM-CSF at 96-138 ng/105 cells/ml 24 hr after GM-CSF gene transfer. GM-CSF gene-modified DCs (DC.GM) exhibited higher expression of B7 and co-stimulatory capacity in mixed lymphocyte reaction (MLR). Fusion of DC.GM with B16 cells generated B16/DC.GM hybrid cells secreting GM-CSF at 59-63 ng/105 cells/ml. Immunization of C57BL/6 mice with the B16/DC hybrid vaccine elicited a specific cytotoxic T-lymphocyte (CTL) response and protected the immunized mice from B16 tumour challenge, reduced pulmonary metastases and extended the survival of B16 tumour-bearing mice. The B16/DC.GM hybrid vaccine was able to induce a CTL response and protective immunity more potently and tended to be therapeutically more efficacious than the B16/DC vaccine. In vivo depletion of T-cell subsets demonstrated that both CD8+ and CD4+ T cells were essential for the therapeutic effects of B16/DC and B16/DC.GM hybrid vaccines. Additionally, other non-specific effector cells may also contribute to tumour rejection induced by the B16/DC.GM hybrid vaccine. These data indicate that a DC-based hybrid tumour vaccine may be an attractive strategy for cancer immunotherapy, and that GM-CSF gene-modified DCs may lead to the generation of hybrid vaccines with potentially increased therapeutic efficacy.
authors.affiliation: Department of Immunology, Second Military Medical University, Shanghai, China.
authors.forename: X
authors.initials: X
authors.lastname: Cao
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: X
authors.initials: X
authors.lastname: Huang
authors.forename: H
authors.initials: H
authors.lastname: Hamada
authors.forename: W
authors.initials: W
authors.lastname: Chen
mesh_terms: D000818:Animals; D019496:Cancer Vaccines / Q000627:therapeutic use*; D002459:Cell Fusion; D002470:Cell Survival; D003602:Cytotoxicity, Immunologic; D003713:Dendritic Cells / Q000276:immunology* / Q000637:transplantation; D005260:Female; D018014:Gene Transfer Techniques; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology*; D016130:Immunophenotyping; D008175:Lung Neoplasms / Q000556:secondary / Q000628:therapy; D007959:Lymphocyte Culture Test, Mixed; D008546:Melanoma, Experimental / Q000276:immunology / Q000628:therapy*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D013154:Spleen / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology
chemical_list: D019496:Cancer Vaccines; D016178:Granulocyte-Macrophage Colony-Stimulating Factor