How the brain guards itself against virus attacks

Infections in the central nervous system are rare thanks to our brain’s unique defence system that prevents viruses from invading, finds a study. The research explains a long-standing mystery. The olfactory mucosa in the nose can serve as a conduit for a number of viruses to enter the brain including rabies, polio and influenza viruses. Yet infections in the central nervous system rarely occur. The mechanism responsible for protecting the brain from viruses that successfully invade the olfactory bulb (OB), the first site of infection in nasal mucosa, remains elusive. “Our work points to the remarkable ability of the immune system, even within the brain, to protect us against opportunistic viruses,” says Anthony van den Pol of Yale University. Van den Pol and his colleagues discovered that in response to viral infection, cells in the olfactory bulb release long-distance signalling molecules that tell cells in uninfected parts of the brain to produce anti-viral interferon – a...