TLR9 Activation Suppresses Inflammation in Response to Helicobacter pylori Infection

Helicobacter pylori (H. pylori) activates Toll-like receptor 9 (TLR9) via translocation of DNA through its main virulence constituent, the cag pathogenicity island. In this study, we utilized Tlr9- and IL-17-deficient mice to demonstrate that H. pylori-induced activation of TLR9 in vivo induces an anti-inflammatory phenotype suppressing IL-17-mediated responses. These results suggest that H. pylori utilizes the cag island to manipulate the intensity of the host immune response.