Antiviral effects of a transgenic RNA-dependent RNA polymerase

Transgenic expression of the RNA-dependent RNA polymerase 3D^pol inhibited infection of Theiler's murine encephalitis virus (TMEV), a picornavirus from which it was derived. Here, we infected 3D^pol transgenic mice with another picornavirus, as well as an alphaherpesvirus and a rhabdovirus. 3D^pol transgenic FVB mice had significantly lower viral loads and survived longer after infection with all three types of viruses than nontransgenic FVB mice. Viral inhibition among three different types of virus by transgenic 3D^pol suggests that the mechanism of action is not the direct interference with picornaviral 3D^pol but instead may be the changing of host cells to an antiviral state before or after viral infection occurs, as basal interferon levels were higher in 3D^pol transgenic mice before infection. Further study of this mechanism may open new possibilities for future antiviral therapy.