Differential susceptibility of equine and mouse brain microvascular endothelial cells to equine herpesvirus 1 infection.

This research paper investigates why equine herpesvirus 1 (EHV-1) affects the central nervous system (CNS) of horses but not mice, by comparing the virus’s impact on endothelial cells from both species. The study found that the virus enters and behaves differently in these cells, suggesting that the method of viral entry plays a significant role in species susceptibility to EHV-1 infection.

Key Research Findings

• The researchers investigated EHV-1, a virus that displays endotheliotropism – a predilection for attacking the endothelial cells – in horses’ central nervous system (CNS).
• However, EHV-1 does not infect endothelial cells in mice’s CNS, a divergence the researchers sought to understand.
• The team compared EHV-1 infection in equine brain microvascular endothelial cells (EBMECs) and mouse brain microvascular endothelial cells (MBMECs).

Viral Growth and Detection

• The scientists observed that the rate of viral growth in EBMECs reflected a fully productive infection, exhibiting the usual progression.
• However, the virus’s presence in the MBMECs seemed to be nonproductive, lacking signs of active viral reproduction.
• Immunofluorescence microscopy – a technique used to visualize antigens in cells – was employed, showing EHV-1 in infected EBMECs but not in MBMECs.

Gene Expression

• The researchers found that EHV-1 immediate early (IE), early (ICP0) and late (gB, gD and gK) genes were expressed in infected EBMECs, indicating the active reproduction and progression of the virus.
• However, these genes were not detected in infected MBMECs, pointing towards the absence of productive EHV-1 replication in these cells.

Viral Entry Stage

• Upon examining the cells using electron microscopy at the viral entry stage, the scientists discovered that viral particles were present within uncoated vesicles (tiny spherical structures) in the cytoplasm of EBMECs.
• In contrast, these viral particles were absent from the MBMECs.
• This observation led to the conclusion that the way a virus enters a cell – in this case, the presence or absence of uncoated vesicles – is a significant factor in determining whether it can establish an infection.