Growth characteristics of a highly virulent, a moderately virulent, and an avirulent strain of equine arteritis virus in primary equine endothelial cells are predictive of their virulence to horses.

This research investigates the growth characteristics of three different strains of Equine Arteritis Virus (EAV) with varied levels of virulence. The study underscores the predictive value of growth characteristics on virulence, and extends the potential of primary equine endothelial cells as a model for studying EVA pathogenesis.

Research Background and Purpose

• The paper focuses on Equine Arteritis Virus (EAV), which can cause a disease in horses known as Equine Viral Arteritis (EVA). EAV is unique in the sense that it has only one serotype but differs largely in virulence across different strains.
• The purpose of this study is to compare the replication and cytopathogenicity (ability to cause disease at the cellular level) of three strains of EAV with different virulence in rabbit kidney cells and primary equine pulmonary artery endothelial cells.

Research Process and Findings

• The researchers used both rabbit kidney (RK-13) cells and primary equine pulmonary artery endothelial cells for the study.
• The results show that viral protein expression, plaque size, and cytopathogenicity of all the three EAV strains were similar when observed in RK-13 cells.
• Contrastingly, in the primary equine endothelial cells (ECs), the two virulent EAV strains could be easily distinguished from the avirulent strain based on their plaque morphology and cytopathogenicity.
• Additionally, it was noted that the nucleocapsid protein of the EAV was detected significantly later in ECs infected with the avirulent strain as compared to those infected with the virulent strains.

Conclusion and Implications

• Based on these findings, the paper implies that the growth characteristics of EAV in primary equine endothelial cells are predictive of their level of virulence to horses, thus laying foundation for predictive models.
• The study also suggests that primary equine ECs can be useful for in vitro (lab-grown) characterization of EVA pathogenesis (development of the disease) and for studying the virulence determinants of EAV, potentially helping in development of future treatment methods.