last updated April 2013
Putting up barriers against invading pathogens
An international team of researchers uncovers how epithelial surfaces are protected from destructive bacterial infection
Defense against bacterial infections on the lining of surfaces in the lung requires signaling molecules produced by immune leukocytes called ‘TH17 cells’, an international research team reports in a recent issue of Nature Medicine1. The team has clarified how immune cells cooperate with cells in the lining—or mucosa—of the lung to maintain a protective barrier against bacterial invasion.
Jay Kolles at the Children’s Hospital of Pittsburg, USA, Yoichiro Iwakura at The Institute of Medical Science, University of Tokyo, and colleagues studied how TH17 cells affect the course of infection specifically at the lung mucosa. Like all mucosal surfaces, the lung mucosa is lined with epithelial ‘skin-like’ cells. Previous studies were mixed on whether TH17 cells promote damaging inflammation or beneficial aid during bacterial infections of mucosal sites.
The team determined that the signaling molecules interleukin-17 and interleukin-22 are important factors produced by TH17 cells and that interleukin-22 in particular is responsible for ‘instructing’ the cellular lining of the lung to produce antibacterial molecules and to thrive.
The significance of this study is that it emphasizes the importance of interleukin-22 and TH17 cells in pneumonia and other types of bacterial infections that target mucosal surfaces of the body.