Cloning and expression of murine IFNβ and a TNF antagonist for gene therapy of experimental allergic encephalomyelitis

Immunomodulation of an ongoing autoimmune disease can be achieved by inhibitory cytokines or cytokine inhibitors such as TNF antagonists, delivered by gene therapy. The aim of this study was to design and test plasmid and retrovirus vectors expressing the mouse IFN beta gene and a chimeric protein containing the extracellular domain of human p55 TNF receptor linked to a murine Ig. These vectors were transiently expressed in COS-7 cells and permanently in amphotropic packaging cell lines or ABH mouse immortalized fibroblasts. Expression levels were assessed by ELISA, Western blotting and biological activity. In order to achieve tissue-specific expression in the CNS, the IFN beta gene was cloned and expressed under the control of the rat NSE promoter. We evaluated these constructs by direct intracranial injections of DNA-liposome complexes during the induction phase of experimental allergic encephalo-myelitis, a murine model of multiple sclerosis, with therapeutic benefit.