433. DNA Monoclonal Antibodies Target Influenza Virus In Vivo

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Despite promising innovations, influenza vaccines and antiviral drugs fail to provide full protection from seasonal infection, and provide little defense against novel and potentially pandemic viral strains. Broadly cross-protective monoclonal antibodies have been developed with the aim of providing protection against highly divergent influenza viruses. However, the utility of delivering purified protein antibody as therapy or prophylaxis against influenza is limited, especially in pandemic settings. Use of gene therapy to generate monoclonal antibodies in vivo provides a simplified, flexible, and relatively inexpensive alternative to protein antibody treatment.In this study, we used intramuscular electroporation of plasmid DNA encoding immunoglobulin to express DNA monoclonal antibodies (DMAb) against influenza hemagglutinin (HA) surface protein in mice. Multiple aspects of plasmid construction, antibody design, and delivery were optimized to enhance expression of DMAb from muscle cells in vivo. We investigated multiple antibody clones, including the broadly-neutralizing anti-influenza-H1 antibody 5J8. The 5J8 DMAb was expressed at µg/mL levels in serum of both nude and immune-competent mice. Serum DMAb produced from muscle in vivo were functional in vitro - with the ability to bind influenza HA, block hemagglutination of red blood cells, and neutralize influenza virus. Serum DMAb expression levels approximate those required for protection. Influenza challenge studies of mice treated with 5J8 DMAb are underway.DMAb provide an important new approach to immune therapy. DNA has an excellent safety profile and averts challenges of pre-existing serology associated with many viral vectors. Here, we demonstrate that DNA can be used to deliver consistently high levels of potent monoclonal antibodies for protection against a viral pathogen.