Stat1-Deficient Mice Are Not an Appropriate Model for Efficacy Testing of Recombinant Vesicular Stomatitis Virus-Based Filovirus Vaccines

Stat1^-/- mice lack a response to interferon α, β, and γ, allowing for replication of nonadapted wild-type (wt) Ebolavirus and Marburgvirus. We sought to establish a mouse model for efficacy testing of live attenuated recombinant vesicular stomatitis virus (rVSV)-based filovirus vaccine vectors using wt Ebolavirus and Marburgvirus challenge strains. While infection of immunocompetent mice with different rVSV-based filovirus vectors did not cause disease, infection of Stat1^-/- mice with the same vectors resulted in systemic infection and lethal outcome for the majority of tested rVSVs. Despite differences in viral loads, organ tropism was remarkably similar between rVSV filovirus vaccine vectors and rVSVwt, with the exception of the brain. In conclusion, Stat1^-/- mice are not an appropriate immunocompromised mouse model for efficacy testing of live attenuated, replication-competent rVSV vaccine vectors.