DNA vaccination against La Crosse virus

For the development of effective conventional vaccines or DNA vaccines agai nst viruses, the availability of suitable animal models is an essential pre requisite. For many recently emerging zoonotic viruses, suitable animal mod els are still missing. We have established a novel small animal model for D NA vaccines using mice lacking a functional interferon-alpha/beta receptor (IFNAR-1). IFNAR-1-deficient mice are highly susceptible to many different viruses despite their ability to mount a normal humoral and cellular immune response. Taking advantage of this animal model, we show that mice can be completely protected from lethal challenge with a single injection of plasm id DNA encoding the viral envelope proteins G1 and G2. By contrast, vaccina tion with a plasmid encoding the internal nucleocapsid protein N had little effect. In an effort to enhance the protective immune response to N we ass essed the efficacy of vaccination with plasmid DNA encoding N in combinatio n with a plasmid encoding the cytokine IL-12 as adjuvant. IL-12 enhanced th e survival of mice following viral challenge, but the effect was independen t of N indicating the involvement of components of the innate immune system such as NK cells. Copyright (C) 2001 S. Karger AG, Basel.