Respiratory syncytial virus creates clumps of dead, bloblike lung cells
With one protein, a common infection in young children caused by respiratory syncytial virus shoves dying lung cells into the airway, where they can create killer clogs.
The blockages are a hallmark of RSV infections, which cause lower airway disease in 34 million infants and young children worldwide annually, resulting in approximately 200,000 deaths. But until now, scientists didn't know exactly how the virus blocked breathing.
Using human lung cells growing in the lab, Raymond Pickles of the University of North Carolina at Chapel Hill and colleagues found that the virus infects only the lung’s top layers of cells. These cells usually secrete antimicrobials and wave their hairlike cilia to move mucus up and out of the lung.
Once infected, Pickles and colleagues discovered, the cells transform from tightly packed rectangles, like bricks in a wall, to spherical globs that spill into the airway. The researchers tested mutant RSV viruses and found that a single gene that makes a protein called NS2 causes the cellular congestion.
The authors say the finding, reported April 8 in the Journal of Clinical Investigation, could help researchers develop therapies for RSV infections, which currently have no targeted treatment or vaccine.
R. M. Liesman, et al. RSV-Encoded NS2 promotes epithelial cell shedding and distal airway obstruction. Journal of Clinical Investigation. Published online April 8, 2014. doi: 10.1172/JCI72948.
N. Seppa. Dog dust may benefit infant immune systems. Science News. Vol. 185, January 25, 2014, p. 8.