title: Effective immunization against neuroblastoma using double-transduced tumor cells secreting GM-CSF and interferon-gamma.
abstract: Murine neuroblastoma, neuro-2a, was transduced with the retroviral vector MFG-granulocyte-macrophage colony-stimulating factor (GM-CSF), to examine immune stimulation conferred by localized GM-CSF production. Expression of murine GM-CSF by neuro-2a (N-2a/GM) significantly reduced its tumorigenicity. Moreover, immunization of mice with irradiated N-2a/GM cells resulted in a significant protective effect against live tumor challenge 14 days later. Approximately 41% of mice immunized with irradiated N-2a/GM versus 0% of those vaccinated with irradiated parental tumor survived. Surviving mice were rechallenged after 50 days with wild-type neuro-2a or with the Sa1 syngeneic sarcoma to discern whether the generated immunity was durable and tumor specific. All mice survived wild-type neuro-2a challenge, whereas none survived inoculation with Sa1. Because both CD4+ and CD8+ T cells were necessary during priming to this MHC class Ilo, II-tumor, these data indicate that major histocompatibility complex (MHC) class I+, II+ antigen-presenting cells (APCs) were required for the T-cell antitumor response. Co-expression of GM-CSF and IFN-gamma, both of which have immunostimulatory activities on antigen-presenting cells, abrogated the tumorigenic potential of this tumor and increased immunogenicity over N-2a/IFN but not N-2a/GM. Vaccination of mice with preexisting retroperitoneal tumors with irradiated N-2a/GM and irradiated N-2a/IFN/GM improved survival. There was a trend for nonirradiated transduced cells to be more immunogenic than their irradiated counterparts. Immunohistochemistry of tissues from the vaccination site revealed a pronounced macrophage infiltration associated with nonirradiated N-2a/GM and N-2a/IFN/GM. These data suggest that vaccination involving nonirradiated neuroblastoma cells transduced with genes that stimulate APCs may be a useful approach in stimulating antitumor T-cell responses.
authors.affiliation: Department of Pediatrics, University of Minnesota, Minneapolis 55455, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Bausero
authors.forename: A
authors.initials: A
authors.lastname: Panoskaltsis-Mortari
authors.forename: B R
authors.initials: BR
authors.lastname: Blazar
authors.forename: E
authors.initials: E
authors.lastname: Katsanis
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology*; D005434:Flow Cytometry; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008805:Mice, Inbred A; D009447:Neuroblastoma / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control*; D014162:Transfection / Q000276:immunology; D014407:Tumor Cells, Cultured; D014614:Vaccines, Synthetic / Q000276:immunology*
chemical_list: D019496:Cancer Vaccines; D014614:Vaccines, Synthetic; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor