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Intramuscular administration of expression plasmids encoding interferon‐γ receptor/IgG1 or IL‐4/IgG1 chimeric proteins protects from autoimmunity
Author(s) -
Chang Yigang,
Prud'homme Gérald J.
Publication year - 1999
Publication title -
the journal of gene medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.689
H-Index - 91
eISSN - 1521-2254
pISSN - 1099-498X
DOI - 10.1002/(sici)1521-2254(199911/12)1:6<415::aid-jgm66>3.0.co;2-b
Subject(s) - plasmid , autoimmunity , antibody , receptor , immunology , fusion protein , biology , interferon , recombinant dna , virology , microbiology and biotechnology , medicine , gene , genetics
Background Interferon γ (IFNγ) is an inflammatory cytokine that promotes autoimmune insulitis and diabetes in NOD mice, while interleukin‐4 (IL‐4) is protective. We constructed plasmids encoding either an IFNγ receptor/IgG1 (IFNγR/IgG1) chimeric protein which inhibits IFNγ, or an IL‐4/IgG1 chimeric protein with IL‐4 activity, for therapeutic gene transfer into NOD mice. Methods Murine IFNγR/IgG1 and IL‐4/IgG1 cDNA segments were cloned into the VICAL VR1255 expression plasmid. Naked plasmid DNA was injected i.m. into young NOD mice, which were then observed for development of insulitis and diabetes. Results After transient transfection of COS‐7 cells, IFNγR/IgG1 and IL‐4/IgG1 fusion proteins are secreted in vitro as disulfide‐linked homodimers, with the expected biological activity. Intramuscular injection of these vectors results in the production of the respective fusion proteins locally in muscle. In serum, the IFNγR/IgG1 protein is present at >200 ng/ml over 130 days after the last of five DNA injections, but IL‐4/IgG1 is undetectable in our assays (<10 pg/ml) at all time points. Both vectors protect NOD mice from autoimmune insulitis and diabetes, but the IL‐4/IgG1 vector is more effective. Neutralization of IFNγ with IFNγR/IgG1 was most protective when treatment was begun early (3 weeks of age). Conclusion Gene therapy by i.m. injection of these plasmids protects NOD mice from autoimmunity, and the IL‐4/IgG1 vector is more effective despite low circulating protein levels. These chimeric proteins consist of nonimmunogenic self elements and are suitable for long‐term therapy of autoimmune disorders. Copyright © 1999 John Wiley & Sons, Ltd.