title: The Ch14.18-GM-CSF fusion protein is effective at mediating antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity in vitro.
abstract: Granulocyte/macrophage-colony stimulating factor (GM-CSF) is very effective at enhancing antibody-dependent cellular cytotoxicity (ADCC) mediated by granulocytes and monocytes. Recently, a fusion protein consisting of GM-CSF and chimeric human/mouse anti-ganglioside G(D2) antibody Ch14.18 (Ch14.18-GM-CSF) has been generated to improve the effectiveness of immunotherapy by directing GM-CSF to the tumor microenvironment and prolonging its relatively short half-life. In this study, we examined the ability of this fusion protein to enhance the in vitro killing of G(D2)-expressing human neuroblastoma cells by granulocytes and mononuclear cells, as well as by complement. The Ch14.18-GM-CSF fusion protein was equally effective as the combination of equivalent amounts of free Ch14.18 and GM-CSF in mediating the killing of NMB7 neuroblastoma cells by granulocytes from seven of eight neuroblastoma patients. The fusion protein was also equally effective as the combination of Ch14.18 and GM-CSF in mediating ADCC by neuroblastoma patients' mononuclear cells. In addition, the fusion protein was as effective as Ch14.18 alone in directing complement-dependent cytotoxicity against NMB7 cells. Our results demonstrate that the biological activities expressed by ADCC and complement-dependent cytotoxicity of both monoclonal antibody Ch14.18 and GM-CSF are retained by the Ch14.18-GM-CSF fusion protein and lend further support for future clinical trials of this fusion protein in patients with neuroblastoma.
authors.affiliation: Department of Pediatrics, University of California, San Diego 92103-8447, USA.
authors.forename: A
authors.initials: A
authors.lastname: Batova
authors.forename: A
authors.initials: A
authors.lastname: Kamps
authors.forename: S D
authors.initials: SD
authors.lastname: Gillies
authors.forename: R A
authors.initials: RA
authors.lastname: Reisfeld
authors.forename: A L
authors.initials: AL
authors.lastname: Yu
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism; D000920:Antibody-Dependent Cell Cytotoxicity / Q000276:immunology*; D003165:Complement System Proteins / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005732:Gangliosides / Q000276:immunology / Q000378:metabolism; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000276:immunology / Q000494:pharmacology*; D006098:Granulocytes / Q000276:immunology; D006801:Humans; D018796:Immunoconjugates / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D009447:Neuroblastoma / Q000097:blood / Q000276:immunology / Q000473:pathology; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D000276:Adjuvants, Immunologic; D000911:Antibodies, Monoclonal; D005732:Gangliosides; D018796:Immunoconjugates; D011993:Recombinant Fusion Proteins; C019403:ganglioside, GD2; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D003165:Complement System Proteins