Hide And Seek: Researchers Discover A New Way For Infectious Bacteria To Enter Cells

French scientists have learned how Listeria monocytogenes, which causes a major food-borne illness, commandeers cellular transport machinery to invade cells and hide from the body's immune system. They believe that other infectious organisms may use the same mechanism. The Listeria bacterium, found in soil and water, can be transmitted to humans via undercooked and unpasteurized food, causing flu-like symptoms or gastrointestinal distress. For individuals with weakened immune systems, listeriosis can be fatal, and infections during pregnancy can lead to miscarriage, stillbirth, premature delivery, or infection of the newborn. The research was conducted by Pascale Cossart, a Howard Hughes Medical Institute international research scholar, and her colleague Esteban Veiga at the Institut Pasteur in Paris, and will be published in the August 21, 2005, issue of Nature Cell Biology. Cossart and Veiga detailed how Listeria invades cells by activating cellular machinery that transports viruses, small molecules, and proteins. Once it has safely entered a cell, the microbe can replicate and continue the process of infection.