title: Recombinant anti-human HER2/neu IgG3-(GM-CSF) fusion protein retains antigen specificity and cytokine function and demonstrates antitumor activity.
abstract: Anti-HER2/neu therapy of human HER2/neu-expressing malignancies such as breast cancer has shown only partial success in clinical trials. To expand the clinical potential of this approach, we have genetically engineered an anti-HER2/neu IgG3 fusion protein containing GM-CSF. Anti-HER2/neu IgG3-(GM-CSF) expressed in myeloma cells was correctly assembled and secreted. It was able to target HER2/neu-expressing cells and to support growth of a GM-CSF-dependent murine myeloid cell line, FDC-P1. The Ab fusion protein activated J774.2 macrophage cells so that they exhibit an enhanced cytotoxic activity and was comparable to the parental Ab in its ability to effect Ab-dependent cellular cytotoxicity-mediated tumor cell lysis. Pharmacokinetic studies showed that anti-HER2/neu IgG3-(GM-CSF) is stable in the blood. Interestingly, the half-life of anti-HER2/neu IgG3-(GM-CSF) depended on the injected dose with longer in vivo persistence observed at higher doses. Biodistribution studies showed that anti-HER2/neu IgG3-(GM-CSF) is mainly localized in the spleen. In addition, anti-HER2/neu IgG3-(GM-CSF) was able to target the HER2/neu-expressing murine tumor CT26-HER2/neu and enhance the immune response against the targeted Ag HER2/neu. Anti-HER2/neu IgG3-(GM-CSF) is able to enhance both Th1- and Th2-mediated immune responses and treatment with this Ab fusion protein resulted in significant retardation in the growth of s.c. CT26-HER2/neu tumors. Our results suggest that anti-HER2/neu IgG3-(GM-CSF) fusion protein is useful in the treatment of HER2/neu-expressing tumors.
authors.affiliation: Departments of Microbiology and Molecular Genetics, and The Molecular Biology Institute, University of California, Los Angeles, CA 90095, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Dela Cruz
authors.forename: K R
authors.initials: KR
authors.lastname: Trinh
authors.forename: S L
authors.initials: SL
authors.lastname: Morrison
authors.forename: M L
authors.initials: ML
authors.lastname: Penichet
mesh_terms: D000230:Adenocarcinoma / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000096:biosynthesis; D000912:Antibodies, Neoplasm / Q000008:administration & dosage* / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000138:chemical synthesis* / Q000493:pharmacokinetics; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D003110:Colonic Neoplasms / Q000276:immunology / Q000473:pathology / Q000517:prevention & control; D016207:Cytokines / Q000502:physiology*; D003602:Cytotoxicity, Immunologic / Q000235:genetics; D000939:Epitopes / Q000276:immunology* / Q000378:metabolism; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage / Q000235:genetics*; D006207:Half-Life; D006801:Humans; D007074:Immunoglobulin G / Q000008:administration & dosage / Q000235:genetics*; D007132:Immunoglobulin Isotypes / Q000096:biosynthesis / Q000145:classification; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000138:chemical synthesis / Q000276:immunology* / Q000493:pharmacokinetics; D014407:Tumor Cells, Cultured
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000912:Antibodies, Neoplasm; D000970:Antineoplastic Agents; D016207:Cytokines; D000939:Epitopes; D016178:Granulocyte-Macrophage Colony-Stimulating Factor; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C048844:anti-IgG