Researchers at King’s College London (KCL) and the Francis Crick Institute have uncovered details about how airway cells defend the body from rhinovirus infection.
While we are in the midst of the infamous freshers’ flu season, KCL researchers have gained an insight into how airway epithelial tissue (a layer of cells covering outer body surfaces, organs and internal cavities) defends the body from the common cold.
A key finding of the study is that airway cells protect the body from rhinovirus infections in two stages. They extrude – or push – the infected cells out of the tissue. Researchers refer to this as virus-induced cell extrusion (VICE). This response expels the majority of infected cells from the body’s airway lining within 24 hours.
The first stage happens almost immediately, before the incoming virus has completely entered the cell. The second stage happens later on, once the virus replicates itself inside the cell and has caused cell death.
However, this does not mean the virus will immediately leave the body. The researchers also found that the ejected cells survive. They remain infectious and could possibly still be able to find new cells to attack.
The rhinovirus is the leading cause of the common cold, usually causing mild illness. However, they can prove more detrimental for the respiratory systems of young children and older people, as well as individuals with weakened immune systems or chronic lung conditions (e.g. asthma, chronic obstructive pulmonary disease).
The discovery proves significant because it reveals a new method of the airway lining – the body’s first physical barrier against threats such as viruses – to protect the tissue by removing infected cells.
The airway lining was priorly known to detect infections and regulate the body’s immune system response. This study sheds more light on how the airway lining defends against respiratory viruses, by demonstrating that airway cells also act by physically ejecting infected cells.
According to the researchers, physical extrusion of infected cells by epithelial tissue was not comprehensively explored while researching viral infection. Instead, previous studies usually focused on how immune cells, such as innate lymphoid cells, protect the body from threats, including rhinovirus-induced asthma exacerbations.
A necessary extension to this study is determining whether tissue uses the same technique to protect against other respiratory viruses. Another one would be how viruses respond to it or defend against it.
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