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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenocarcinoma / immunology
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Adenocarcinoma / pathology
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Adenocarcinoma / prevention & control
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Animals
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Antibodies, Anti-Idiotypic / biosynthesis
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Antibodies, Neoplasm / administration & dosage*
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Antibodies, Neoplasm / biosynthesis
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Antibodies, Neoplasm / chemistry
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Antibodies, Neoplasm / genetics*
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Antineoplastic Agents / administration & dosage
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Antineoplastic Agents / chemical synthesis*
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Antineoplastic Agents / pharmacokinetics
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Cell Division / genetics
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Cell Division / immunology
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Cell Line
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Cell Membrane / genetics
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Cell Membrane / immunology
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Cell Membrane / metabolism
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Colonic Neoplasms / immunology
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Colonic Neoplasms / pathology
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Colonic Neoplasms / prevention & control
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Cytokines / physiology*
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Cytotoxicity, Immunologic / genetics
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Epitopes / immunology*
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Epitopes / metabolism
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Female
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Granulocyte-Macrophage Colony-Stimulating Factor / administration & dosage
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Granulocyte-Macrophage Colony-Stimulating Factor / genetics*
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Half-Life
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Humans
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Immunoglobulin G / administration & dosage
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Immunoglobulin G / genetics*
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Immunoglobulin Isotypes / biosynthesis
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Immunoglobulin Isotypes / classification
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Injections, Intravenous
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Injections, Subcutaneous
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Macrophages / immunology
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Mice
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Mice, Inbred BALB C
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Protein Binding / genetics
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Protein Binding / immunology
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Receptor, ErbB-2 / administration & dosage
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Receptor, ErbB-2 / genetics
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Receptor, ErbB-2 / immunology*
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Recombinant Fusion Proteins / administration & dosage
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Recombinant Fusion Proteins / chemical synthesis
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Recombinant Fusion Proteins / immunology*
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Recombinant Fusion Proteins / pharmacokinetics
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Tumor Cells, Cultured
Substances
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Antibodies, Anti-Idiotypic
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Antibodies, Neoplasm
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Antineoplastic Agents
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Cytokines
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Epitopes
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Immunoglobulin G
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Immunoglobulin Isotypes
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Recombinant Fusion Proteins
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anti-IgG
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Granulocyte-Macrophage Colony-Stimulating Factor
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Receptor, ErbB-2