Recombinant lymphocytic choriomeningitis virus-based vaccine vector protects type I interferon receptor deficient mice from viral challenge.

Reverse genetically engineered recombinant lymphocytic choriomeningitis virus (rLCMV) is a novel vaccine vector platform. Here, we investigate the safety and efficacy of rLCMV in mice lacking a functional type I interferon system with high susceptibility to viral infections. Propagation-deficient rLCMV vector expressing ovalbumin as a model antigen is cleared from type I interferon receptor-deficient mice (Ifnar) within seven days post vaccination. In Ifnar, induction of vaccine antigen specific T cells is delayed compared to wild type animals. However, immunization of Ifnar results in potent memory formation and generates multifunctional cytotoxic CD8 T cells. Most importantly, Ifnar vaccinated with rLCMV are protected from a challenge with the aggressive LCMV Clone 13. Our data provide evidence for an excellent safety profile with maintained efficacy in immunocompromised animals.