Читать книгу Principles of Virology, Volume 2 - Jane Flint, S. Jane Flint - Страница 72

Neurons within the olfactory mucosa are a potential entry point for respiratory viruses that can replicate in neurons, including measles, mumps, rubella, and varicella-zoster virus. Olfactory neurons are unusual in that their cell bodies are present in the olfactory epithelia and their axon termini are in synaptic con tact with olfactory bulb neurons. The olfactory nerve fiber passes through the skull via an opening called the arachnoid, and thus viruses that are present within the nasal mucosa are just one synapse away from the brain. Yet infections of the central nervous system (CNS) rarely occur. Why aren’t CNS infections more common via this route? Studies in mice have revealed some mechanisms that may prevent this potentially catastrophic outcome. Infection of mice with a neurotropic strain of influenza A Olfactory mucosa Mitral cell neurons of olfactory bulb Receptor cell axon terminal Subarachnoid space Dura Cribriform plate Receptor cell axon Receptor cell body Olfactory rods virus resulted in rapid apoptosis (cell suicide) of olfactory bulb neurons, coincident with activation of local phagocytes. Mice survived the challenge, raising the possibility that early activation of apoptotic pathways in olfactory neurons may prevent spread of influenza into the brain. Moreover, infection with both RNA and DNA viruses triggers the induction of long distance interferon signaling. Even in the absence of neurotropic virus infection, interferon stimulated proteins are synthesized in remote, posterior regions of the brain, activating an antiviral state and preventing further virus invasion.

 Mori I, Goshima F, Imai Y, Kohsaka S,Sugiyama T, Yoshida T, Yokochi T, Nishiyama Y, Kimura Y. 2002. Olfactory receptor neurons prevent dissemination of neurovirulent influenza A virus into the brain by undergoing virus-induced apoptosis. J Gen Virol 83: 2109–2116.

 van den Pol AN, Ding S, Robek MD. 2014. Long-distance interferon signaling within the brain blocks virus spread. J Virol 88:3695–3704.