Human autologous in vitro models of glioma immunogene therapy using B7-2, GM-CSF, and IL12.
BACKGROUND
Cancer immunogene therapy is based on vaccination with radiated, autologous tumor cells transduced with immunostimulatory genes. To help determine an optimal glioma immunogene therapy strategy, we stimulated lymphocytes with autologous human glioma cells transduced with B7-2 (CD86), granulocyte-macrophage colony-stimulating factor (GM-CSF), and/or interleukin-12 (IL12).


METHODS
A human glioma-derived cell culture (Ed147.BT) was transduced with B7-2, GM-CSF, and/or IL12 using retroviral vectors. Autologous peripheral blood mononuclear cells (PBMC) were co-cultured with irradiated gene-transduced tumor alone or a combination of radiated wild type and gene-transduced cells. Peripheral blood mononuclear cells proliferation was determined by serial cell counts. Peripheral blood mononuclear cells phenotype was assessed by flow cytometry for CD4, CD8, and CD16. Anti-tumor cytotoxicity was determined by chromium-51 (51Cr) release assay.


RESULTS
Peripheral blood mononuclear cells cell numbers all decreased during primary stimulation but tumor cells expressing B7-2 or GM-CSF consistently caused secondary proliferation. Tumors expressing B7-2 and GM-CSF or B7-2, GM-CSF, and IL12 consistently increased PBMC CD8+ (cytotoxic T) and CD16+ (natural killer) percentages. Interestingly, anti-tumor cytotoxicity only exceeded that of PBMC stimulated with wild type tumor alone when peripheral blood mononuclear cells were stimulated with both wild type tumor and B7-2/GM-CSF- (but not IL12) transduced cells.


CONCLUSIONS
PBMC proliferation and phenotype is altered as expected by exposure to immunostimulatory gene-transduced tumor. However, transduced tumor cells alone do not stimulate greater anti-tumor cytotoxicity than wild type tumor. Only B7-2/GM-CSF-transduced cells combined with wild type produced increased cytotoxicity. This may reflect selection of tumor subclones with limited antigenic spectra during retrovirus-mediated gene transfer.
Division of Neurosurgery, Department of Surgery, 2D1.02 W.C. Mackenzie Health Sciences Center, University of Alberta, Edmonton, Alberta, Canada T6G 2R7.
Ian F
IF
Parney
Maxine A
MA
Farr-Jones
Kevin
K
Kane
Lung-Ji
LJ
Chang
Kenneth C
KC
Petruk
D000276:Adjuvants, Immunologic / Q000235:genetics / Q000627:therapeutic use*; D020533:Angiogenesis Inhibitors / Q000235:genetics / Q000627:therapeutic use*; D015703:Antigens, CD / Q000235:genetics / Q000627:therapeutic use*; D051940:B7-2 Antigen; D019496:Cancer Vaccines / Q000627:therapeutic use; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D005910:Glioma / Q000235:genetics / Q000276:immunology / Q000628:therapy*; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000627:therapeutic use*; D006801:Humans; D007167:Immunotherapy / Q000379:methods*; D018664:Interleukin-12 / Q000235:genetics / Q000627:therapeutic use*; D008562:Membrane Glycoproteins / Q000235:genetics / Q000627:therapeutic use*; D010641:Phenotype; D014161:Transduction, Genetic; D014407:Tumor Cells, Cultured
D000276:Adjuvants, Immunologic; D020533:Angiogenesis Inhibitors; D015703:Antigens, CD; D051940:B7-2 Antigen; C497964:CD86 protein, human; D019496:Cancer Vaccines; D008562:Membrane Glycoproteins; D018664:Interleukin-12; D016178:Granulocyte-Macrophage Colony-Stimulating Factor