Neurotropic RNA Virus Modulation of Immune Responses within the Central Nervous System

Figures

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  Figure 1. RNA viruses can be neurotropic. (A). Schematic of RNA virus entry into the central nervous system (CNS). Neurotropic viruses can infect human hosts via at least two routes of transmission: (1) respiratory droplets or (2) through the bite of an infected insect vector. Upon entry through the blood–brain barrier (BBB) and into the CNS, viruses can infect several CNS cell types, including astrocytes, microglia, and neurons. (B). Schematic of known immune modulation strategies enacted by viruses within the CNS. Arrows indicate activation while blunt-end arrows represent inhibition. Blue blocks indicate a strategy that can either increase or decrease interferon, while purple blocks indicate a strategy that decreases interferon. Created with BioRender.com.

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  Figure 2. Neurotropic RNA virus evasion of IFN-β induction and responses in the CNS. Several RNA viruses can bypass the blood–brain barrier (BBB) through the circulatory system and enter the cells of the central nervous system (CNS). We also note that viral entry into the CNS may occur through other routes in addition to the circulatory vessels depicted within microglia; these viruses can block (red inhibitory arrows) components of the RIG-I signaling pathway, blocking IFN-β induction and subsequent JAK-STAT interferon signaling. Black arrows indicate subsequent steps within the signaling pathway or translocation from the cytoplasm to the nucleus. Created with BioRender.com.