Impact of equine herpesvirus type 1 (EHV-1) infection on the migration of monocytic cells through equine nasal mucosa.

This research examines how equine herpesvirus type 1 (EHV-1) affects the movement of certain cells through a horse’s nasal mucosa, demonstrating the herpesvirus’ potential to exploit mucosal immunity processes to spread throughout the body.

Overview of Research

• The article studies the process by which pathogens, especially viruses, infiltrate a host through its mucosal surfaces. This study specifically relates to the equine herpesvirus type 1 (EHV-1) and its effect on a horse’s nasal cells.
• The study is centered around the movement of antigen-presenting cells (APCs), which play a crucial role in immunity, across the epithelium, a key aspect of the body’s defensive system against infections.

Research Model and Procedure

• The researchers created an ex vivo explant model—a model using living tissue outside of the organism—to understand the movement of monocytic cells across the nasal mucosal epithelium and lamina propria (a layer of connective tissue supporting the epithelium).
• They labeled various specific cells with a fluorescent dye for tracking: equine nasal mucosal CD172a(+) cells (nmCD172a(+) cells), blood-derived monocytes, and monocyte-derived DCs (moDCs), and placed them at the apical part of the polarized mucosal explant.
• The research team used confocal imaging—the method of imaging one plane or slice of a sample—to monitor migration patterns, focusing on the disparities between mock-inoculated (control) cells and those inoculated with EHV-1.

Findings

• The researchers found that 16-26% of mock-inoculated nmCD172a(+) cells and moDCs moved into the nasal epithelia and 1-7% further into the lamina propria. The migration of EHV-1 inoculated monocytic cells showed no increased movement in these tissues compared to the mock groups.
• Following the addition of moDCs and nmCD172a(+) cells, IEP(+) cells were observed beneath the basement membrane (BM) 48 hrs post-inoculation, although no such activity was noted with blood-derived monocytes. The IEP(+) cells indicate early-stage virus infection.
• The findings suggest that monocytic cells can get infected with EHV-1 in the respiratory mucosa and carry the virus from the epithelium to the lamina propria and eventually to the lymph and blood circulation.