Brain prepares for viral attack within hours of distant infection ^{CEFR A2}

A team led by Charles M. Rice at Rockefeller used mice to study how the brain senses infection. They injected West Nile virus (WNV) into mouse footpads and checked brains at several times. Within hours, antiviral genes called ISGs were active in the brain even though the virus was not detectable there.

Scientists tested patterns from microbes, called PAMPs, in the footpad. The brain reacted differently to different signals. When mice received the viral simulant poly(I:C) in the footpad and were later infected in the brain, more mice survived. This protection showed up for WNV, Powassan virus and for herpes simplex in these tests. The authors say the blood-brain barrier can act like an immune sensor and this idea might help prevent vector-borne brain inflammation.