Nature Immunology pp 535 - 672

New information on the complex interplay between host cells and bacteria during infection is reported in the June issue of Nature Immunology. Three studies provide a new understanding of the relationship between salmonella bacteria and the cells infected.

Host cells use special 'sensors' to detect unique components of invading bacteria and alert the rest of the body to the infection by triggering inflammation. Bacteria produce flagellin, a protein that bundles together to form the flagellum, a tail that allows bacteria to swim.

Teams led by Alan Aderem and Gabriel Nunez find that when salmonella bacteria infect a host cell, flagellin released from the bugs is detected by a sensor that triggers inflammation. In a complementary study, work from Ayub Qadri's laboratory shows that host cells produce a lipid that 'tricks' salmonella into secreting flagellin so that the bugs can be detected by the host sensor, triggering an immune response. These studies provide exciting new details of how bacteria cause inflammation and how host cells are actively involved in that process.