Inhaling bacteria increases the production of mucus and liquid that trap and kill microbes in the airways.

A team led by Juan Ianowski at the University of Saskatchewan in Saskatoon, Canada, developed an imaging technique to visualize the depth of the protective layer that lines the airways. The researchers found that when the bacterium Pseudomonas aeruginosa was introduced into isolated pig tracheas, the airways secreted more of this film than unexposed tracheas.

The results could explain why patients with cystic fibrosis, who do not produce this layer properly, are prone to respiratory infections and inflammation. Boosting this previously unknown part of the immune response in these patients could improve their lung function, the authors say.

Proc. Natl Acad. Sci. USA http://doi.org/vbc (2014)