N-terminal E-cadherin peptides act as decoy receptors for Listeria monocytogenes

The observation that E-cadherin is the principal epithelial receptor for the bacterial pathogen Listeria monocytogenes led us to investigate whether N-terminal fragments of E-cadherin containing the L. monocytogenes binding domain could inhibit entry of the bacteria into cultured epithelial cells. Here we demonstrate that a conditioned medium from a gastric cancer cell line (Kato III) that carries a truncating CDH-1 mutation 3' of the L. monocytogenes binding domain can inhibit the uptake of the bacteria into Caco-2 cells. The inhibitory activity of the Kato III conditioned medium could be mimicked by incubation of the bacteria with a recombinant 26-kDa N-terminal E-cadherin peptide prior to infection. Furthermore, these data suggest that cleavage of the 80-kDa extracellular domain of E-cadherin from the cell surface may provide an innate form of pathogen defense by acting as a decoy receptor for L. monocytogenes.