A novel DNA vaccine targeting macrophage migration inhibitory factor protects joints from inflammation and destruction in murine models of arthritis

Abstract Objective Previous studies have demonstrated that neutralization of macrophage migration inhibitory factor (MIF) by anti‐MIF antibodies decreases joint inflammation and destruction in a type II collagen–induced arthritis model in mice. The aim of this study was to develop and describe a simple and effective method of active immunization that induces anti‐MIF autoantibodies, which may neutralize MIF bioactivity. Methods We developed a MIF DNA vaccine by introducing oligonucleotides encoding a tetanus toxoid (TTX) Th cell epitope into the complementary DNA sequence of murine MIF. Mice were injected with this construct in conjunction with electroporation. The ability of this immunization to inhibit the development of collagen antibody–induced arthritis (CAIA) in BALB/c mice and spontaneous autoimmune arthritis in interleukin‐1 receptor antagonist (IL‐1Ra)–deficient mice was then evaluated. Results Mice that received the MIF/TTX DNA vaccine developed high titers of autoantibodies that reacted to native MIF. Compared with unvaccinated mice, vaccinated mice also produced less serum tumor necrosis factor α after receiving an intravenous injection of lipopolysaccharide. In addition, vaccination with MIF/TTX DNA resulted in significant amelioration of both CAIA in BALB/c mice and symptoms of autoimmune arthritis in IL‐1Ra–knockout mice. Conclusion These results suggest that MIF/TTX DNA vaccination may be useful for ameliorating the symptoms of rheumatoid arthritis.