Airway lining fights infection by physically removing infected cells, experiments show
The epithelium, a layer of cells that forms a protective barrier between the body and the outside world, was the first organized tissue to evolve. Epithelial cells lining our airways are mainly seen as a structural barrier, but cell biologist Jody Rosenblatt, who runs a lab at the Crick and King's College London, believes their evolutionary history suggests they play a much more active role in…
The airway lining, a protective layer of cells, was the first organized tissue to evolve, according to cell biologist Jody Rosenblatt. These epithelial cells form a structural barrier, but Rosenblatt suspects they play a more active role in combating infections. To test this hypothesis, her team focused on rhinoviruses, the primary cause of the common cold.
These viruses typically lead to mild illness but can cause severe respiratory issues in vulnerable individuals. The study, published in Science Advances, reveals that airway cells respond to rhinovirus infection by physically ejecting infected cells—a process named virus-induced cell extrusion (VICE). When epithelial cells work together, they can remove infected cells and limit infection within the tissue.
However, breaking down the barrier between cells results in increased viral buildup and VICE in mouse lung tissue, indicating relevance in more complex environments. VICE occurs in two waves: an initial response to mechanical changes and a later response to viral replication. This rapid early defense helps remove most infected cells within 24 hours, preserving the barrier.
However, expelled cells remain infectious, potentially allowing the virus to infect new cells. This dual-edged defense, while clearing the immediate infection, could facilitate viral spread. The team found that the presence of cell-to-cell junctions is crucial for VICE to occur, suggesting that laboratory models lacking these junctions might overlook this vital defense mechanism.
Understanding these ancient tissue defense strategies could alter our perception of early viral infection stages.
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