Viruses unable to fuse
Tests with different cell cultures showed that LY6E affects the ability of the virus to fuse with the host cells. “If the virus is unable to fuse with these cells, it can’t cause infection,” explains corresponding author Professor Volker Thiel from the University of Bern.
The validation in an animal model succeeded thanks to a collaboration with the laboratory of John Schoggins at the Southwestern Medical Center of the University of Texas. The experiments conducted there led to the discovery that the mouse variant of the protein called Ly6e is crucial for the protection of immune cells against infections. In the absence of Ly6e, immune cells such as dendritic cells and B-cells become more susceptible to infection and their numbers decrease dramatically. Mice lacking Ly6e in immune cells are highly susceptible to a normally non-lethal mouse coronavirus and succumb to infection.
Understanding basic concepts
The researchers point out that the mouse coronavirus used in the experiment differs significantly from the pathogen causing the current Covid-19 outbreak – for example, it causes hepatisis rather than respiratory disease. Nevertheless, it is widely accepted as a model for understanding the basic concepts of coronavirus replication and immune responses in a living animal.
“Our study provides new insights into how important these antiviral genes are for the control of viral infection and for an adequate immune response against the virus,” say the authors. “Since LY6E is a naturally occurring human protein, we hope that this knowledge will aid the development of therapies that may one day be used to treat coronavirus infections.” A therapeutic approach that mimics the mechanism of action of LY6E may provide a first line of defence against novel coronavirus infections.