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Entry and replication of Japanese encephalitis virus in cultured neurogenic cells
1Department of Ultrastructural Pathology, Walter Reed Army Institute of Research, Washington, DC 20307.
Abstract:
The entry mode and growth pattern of Japanese encephalitis (JE) virus in mouse neuroblastoma N18TG2 cells and mouse neuroblastoma x rat glioma NG108-15 hybrid cells were studied by electron microscopy. At two minutes after inoculation, JE virions adsorbed onto and directly penetrated through the plasma membrane of the hybrid cells, whereas virions did not adsorb nor entered the neuroblastoma cells. Correspondingly, the hybrid cells showed assembling progeny JE virions in the cisternae of rough endoplasmic reticulum (RER) 1 day postinoculation (p.i.) although virions were rarely found on the following days during the experiment. On the other hand, progeny virions did not assemble in the RER cisternae of the neuroblastoma cells throughout the experiment. The morphologic observations, therefore, suggest that (a) the hybrid cells express JE-virus receptors which facilitate the viral attachment onto and entry into the cells, while the neuroblastoma cells do not and (b) JE virus replicates very poorly after the entry into the hybrid cells while it does not replicate at all in the neuroblastoma cells. The virus titrations of the media of the neuroblastoma and hybrid cell cultures showed only titers indicative of residual virus of the inoculum that progressively decreased during the experiment. The present results show therefore that of the two neurogenic cell culture lines studied only the hybrid cell line can be used for the study of viral entry and replication, although it is not suited for virus production. Possible reasons for the poor replication of JE virus in the hybrid cells are discussed.
Insights
Japanese encephalitis (JE) virus enters hybrid cells but not neuroblastoma cells, suggesting hybrid cells have JE-virus receptors. Replication is poor in hybrid cells, making them suitable for entry studies but not virus production.
Area of Science:
- Virology
- Cell Biology
- Neuroscience
Background:
- Japanese encephalitis (JE) virus is a significant cause of viral encephalitis.
- Understanding viral entry mechanisms is crucial for developing antiviral strategies.
- Murine neuroblastoma cell lines are often used to study neuronal function and viral interactions.
Purpose of the Study:
- To investigate the entry mode and replication of JE virus in two distinct neurogenic cell lines: N18TG2 neuroblastoma cells and NG108-15 hybrid cells.
- To determine the suitability of these cell lines for studying JE virus-host interactions.
- To elucidate the cellular mechanisms underlying JE virus entry and replication.
Main Methods:
- Electron microscopy was employed to visualize JE virion interaction with N18TG2 and NG108-15 cells.
- Time-course observations were conducted post-inoculation to track viral entry and assembly.
- Virus titration assays were performed on culture media to quantify viral progeny.
Main Results:
- JE virions directly penetrated the plasma membrane of NG108-15 hybrid cells, while N18TG2 cells showed no viral adsorption or entry.
- Progeny JE virions assembled within the cisternae of the rough endoplasmic reticulum (RER) of hybrid cells one day post-inoculation.
- Neither cell line supported significant JE virus replication, with virus titers decreasing over time in both cultures.
Conclusions:
- NG108-15 hybrid cells possess JE virus receptors facilitating entry, unlike N18TG2 cells.
- JE virus entry into hybrid cells occurs, but replication is limited, making them suitable for studying viral entry mechanisms.
- The N18TG2 neuroblastoma cell line is not permissive to JE virus infection, and the hybrid cell line is not ideal for virus production due to poor replication.