A transgenic model for listeriosis: Role of internalin in crossing the intestinal barrier

Listeria monocytogenes is responsible for severe food-borne infections, but the mechanisms by which bacteria cross the intestinal barrier are unknown. Listeria monocytogenes expresses a surface protein, internalin, that inter acts with a host receptor, E-cadherin, to promote entry into human epitheli al cells. Murine E-cadherin, in contrast to guinea pig E-cadherin, does not interact with internalin, excluding the mouse as a model for addressing in ternalin function in vivo. In guinea pigs and transgenic mice expressing hu man E-cadherin, internalin was found to mediate invasion of enterocytes and crossing of the intestinal barrier. These results illustrate how relevant animal models for human infections can be generated.