Replication kinetics of neuropathogenic and non-neuropathogenic equine herpesvirus type 1 (EHV-1) strains in primary murine neurons and ED cell line.

The research article examines the different effects and replication rates of neuropathogenic and non-neuropathogenic equine herpesvirus type 1 (EHV-1) strains in neuronal cells, aiming to determine if a specific mutation in the viral DNA influences the virus’s behavior.

Background and Aim

• The research was driven by the awareness that EHV-1 causes several issues in horses including respiratory infections, abortion, and neurological disorders. Moreover, past research revealed a correlation between a single-point mutation in the DNA polymerase gene of the virus and its neuropathogenic potential.
• The primary objective of the study was to identify any variance in the ability of neuropathogenic (EHV-1 26) and non-neuropathogenic (Jan-E and Rac-H) EHV-1 strains to infect neuronal cells.

Method & Findings

• The team observed cytopathic effects (CPE) caused by the EHV-1 strains. These included changes in cell morphology, destruction of the actin cytoskeleton, and nuclei degeneration, all of which resulted in focal degeneration.
• It was notable that the EHV-1 26 strain specifically in the culture system caused fusion of affected cells leading to the formation of syncytia (a mass of cytoplasm containing several nuclei and enclosed in a membrane but no internal cell boundaries).
• They employed real-time PCR analysis, a technique that allowed them to monitor the progress of amplification in “real-time”, to examine the replication rates of both the neuropathogenic and non-neuropathogenic EHV-1 strains.
• This analysis showed that both strains of EHV-1 displayed similar replication rates within neurons and ED cells (equine dermal cell line).

Conclusion

• Based on the results, the study suggested that the point mutation in the EHV-1 polymerase gene observed with the neuropathogenic strain does not influence its rate of replication within neurons and ED cells. This indicates that other factors may be involved in the virus’s neuropathogenic potential.