title: Comparative analysis of antigen loading strategies of dendritic cells for tumor immunotherapy.
abstract: Dendritic cells (DCs) loaded with antigens can effectively stimulate host immune responses to syngeneic tumors, but there is considerable controversy as to which forms of antigen-loading are most immunogenic. Here, the authors compared immunotherapeutic reactivities of DCs loaded with a variety of antigen preparations. Because DC maturation stages affect their capacities of antigen processing and presentation, two DC populations were used for the current analysis: in vivo Flt-3 ligand-induced mature DCs and in vitro bone marrow-derived DCs, which were less mature. To facilitate a direct comparison, the LacZ gene-transduced B16 melanoma model system was used, where beta-galactosidase served as the surrogate tumor-rejection antigen. DC loading strategies included pulsing with the beta-galactosidase protein, H-2K restricted peptide, tumor cell lysate, and irradiated tumor cells and fusion of DCs with tumor cells. Our results demonstrated that electrofusion of DCs and tumor cells generated a therapeutic vaccine far superior to other methods of DC loading. For the treatment of 3-day established pulmonary tumor nodules, a single intranodal vaccination plus IL-12 resulted in a significant reduction of metastatic nodules, while other DC preparations were only marginally effective. Immunotherapy mediated by the fusion cells was tumor antigen-specific. Consistent with their therapeutic activity, fusion hybrids were the most potent stimulators to induce specific IFN-gamma secretion from immune T cells. Furthermore, fusion cells also stimulated a small amount of IL-10 production from immune T cells. However, this IL-10 secretion was also induced by other DC preparations and did not correlate with in vivo therapeutic reactivity.
authors.affiliation: Center for Surgery Research, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: Keiji
authors.initials: K
authors.lastname: Shimizu
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kuriyama
authors.forename: Jorgen
authors.initials: J
authors.lastname: Kjaergaard
authors.forename: Walter
authors.initials: W
authors.lastname: Lee
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Suyu
authors.initials: S
authors.lastname: Shu
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D000941:Antigens / Q000276:immunology*; D019496:Cancer Vaccines / Q000276:immunology; D002459:Cell Fusion; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D007167:Immunotherapy / Q000379:methods*; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D000941:Antigens; D019496:Cancer Vaccines; D016753:Interleukin-10; D007371:Interferon-gamma