Identification of target cells of a European equine arteritis virus strain in experimentally infected ponies.

This research paper focuses on identifying the target cells in ponies infected experimentally with a specific strain of Equine arteritis virus (EAV). The research reveals that the virus has a primary attraction towards CD172a(+) and CD3(+) mononuclear leukocytes, and also affects a significant number of endothelial cells in terminal capillaries. This infection likely results in an elevation of vascular permeability, potentially leading to fluid leakage, but does not lead directly to severe vasculitis and hemorrhages.

Objective and Methodology

• The researchers aim to understand the cellular pathogenesis of the equine arteritis virus (EAV). They focus on a specific strain, EAV 08P178, from the European clade-1.
• The research’s objective is to identify which cells the virus primarily targets in ponies experimentally infected with the virus.
• The researchers notably focus on the organs typically targeted by EAV: respiratory tissues with related lymphoid tissues and large intestines. The organs are collected at two different time frames after inoculating the ponies with the virus: 3 and 7 days post infection.
• To identify which cells the virus targets, researchers use a technique called double immunofluorescence staining. This method helps detect the presence of EAV N-protein and one of four cell markers: CD172a for myeloid cells, CD3 for T lymphocytes, IgM for B lymphocytes, and von Willebrand factor for endothelial cells.

Findings

• Based on their analysis of different organs, the researchers observe that around 31-58% and 47-63% of EAV-positive cells were mononuclear leukocytes (mostly CD172a(+) followed by CD3(+)) at 3 and 7 days post infection.
• The study reveals that the virus did not affect endothelial cells present in large blood vessels. However, within terminal capillaries (those with 1-2 endothelial cells per cross section) of the organs studied, about 15-51% of the endothelial cells were EAV-positive.

Conclusions

• The study concludes that the EAV 08P178 strain mainly targets CD172a(+) and CD3(+) mononuclear leukocytes and also affects a large number of endothelial cells present in terminal capillaries.
• The infection of the virus in terminal capillaries could lead to increased vascular permeability. This can cause leakage of fluid, resulting in edema-serous exudate, but it doesn’t lead to severe vasculitis and hemorrhages.