Cracking Listeria's password

Listeria monocytogenes is responsible for a serious food-borne bacterial disease that can be fatal in newborns and the elderly and can induce late-term miscarriages in pregnant women. Despite it's clinical importance the mechanisms by which bacteria cross the intestinal barrier remains unknown. In June 1 Science, Marc Lecuit and colleagues from Institut Pasteur, Paris show that the L. monocytogenes surface protein internalin is a crucial factor in the bacterial penetration of the intestinal epithelial barrier.

Lecuit et al generated transgenic mice that express human E-cadherin — the receptor for the Listeria surface protein internalin — only in enterocytes. No non-transgenic mice died after oral infection with wild-type or mutant L. monocytogenes lacking internalin, but approximately 85% of transgenic mice died following administration of a similar dose of wild-type bacteria. In addition the internalin/human E-cadherin interaction mediated invasion of enterocytes and subsequent intravillous bacterial multiplication, abscess formation and access to mesenteric ...