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Published on: July 24, 2011
Fluorescent Powassan Reporter Viruses Infect Neuron, Astrocyte and Microglial Cell Lines Independent of Attenuating
Autumn Y Laird1, Varvara Kirillov1, Elena E Gorbunova1
1Department of Microbiology and Immunology, Center for Infectious Disease, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY 11794-5222, USA.
Viruses
|July 28, 2026
Summary
Powassan virus (POWV) reporter viruses reveal that an avirulent mutant can infect CNS cells, suggesting neuroinvasion is blocked before cell engagement. These tools aid POWV research and vaccine development.
Area of Science:
- Virology
- Neuroscience
- Infectious Diseases
Background:
- Powassan virus (POWV) is a neurovirulent, tick-borne pathogen causing severe neurological sequelae.
- An avirulent mutant, LI9-D308N, fails to cause lethal disease, but its neuroinvasion mechanism is unclear.
- The D308N mutation affects a cell attachment domain, yet its role in cell tropism and neuroinvasion needs resolution.
Purpose of the Study:
- To engineer fluorescent reporter viruses for Powassan virus (POWV) to study neuroinvasion mechanisms.
- To assess the in vitro infectivity of wild-type (WT) and avirulent POWV reporter viruses in CNS cells.
- To investigate the role of the D308N mutation in POWV cell tropism and neuroinvasion.
Main Methods:
- Engineered fluorescent mScarlet3 and mNeonGreen reporter genes into WT LI9 and avirulent LI9-D308N POWV strains.
- Generated replication-defective reporter POWVs by replacing the NS1 gene with fluorescent genes.
- Assessed the infectivity of reporter viruses in human brain microvascular endothelial cells, pericytes, astrocytes, microglia, and neuronal cells (SH-SY5Y) in vitro.
Main Results:
- Fluorescent reporter POWVs spread focally and nonlytically, reaching high titers and demonstrating stability.
- No difference was observed in the ability of WT LI9-mScarlet3 and avirulent LI9-D308N-mScarlet3 viruses to infect various CNS and blood-brain barrier cells in vitro.
- WT LI9-mScarlet3 viruses productively and persistently infected neuron-like SH-SY5Y cells without apparent cytotoxicity.
Conclusions:
- The avirulent LI9-D308N mutant can infect blood-brain barrier and CNS cells, indicating neuroinvasion is restricted prior to cell engagement.
- The D308N mutation may interfere with potential neuroinvasion routes or the virus is cleared from the blood.
- Fluorescent POWV reporter viruses are valuable tools for studying POWV neuroinvasion, cell tropism, and developing potential vaccines.
