Mammalian peptidoglycan recognition protein TagL inhibits Listeria monocytogenes invasion into epithelial cells.

Peptidoglycan recognition proteins are a family of evolutionary conserved proteins that play a basic role in the innate immunity of insects, but their role in the immunity of mammals remains unclear. To elucidate its functions, a mouse member of the peptidoglycan recognition proteins family, TagL, was stably expressed in colon adenocarcinoma HT29 cells, and its effect on the invasion and intracellular growth of the enteroinvasive pathogenic bacterium Listeria monocytogenes was assessed. The expression of TagL substantially impaired bacterial invasion and early intracellular growth.

[Effect of the constitutive activity of pathogenicity genes in Listeria monocytogenes].

The effect of the constitutive expression of pathogenicity factors in L. monocytogenes was studied on the model of the intraperitoneal infection of mice. The constitutive expression was due to a single amino acid substitution in the transcriptional factor PfrA, the master regulator of L.