DNA-Dependent Interferon Induction and Lung Inflammation in Infection.

Pertussis, caused by , is a resurgent respiratory disease but the molecular mechanisms underlying pathogenesis are poorly understood. We recently showed the importance of type I and type III interferon (IFN) induction and signaling for the development of lung inflammation in -infected mouse models. Classically, these IFNs are induced by signaling through a variety of pattern recognition receptors (PRRs) on host cells. Here, we found that the PRR signaling adaptor molecules MyD88 and TRIF contribute to IFN induction and lung inflammatory pathology during infection. However, the PRRs Toll-like receptors (TLR) 3 and TLR4, which signal through TRIF and MyD88, respectively, played no role in IFN induction. Instead, the DNA-sensing PRRs, TLR9 and STING, were important for induction of type I/III IFN and promotion of inflammatory pathology, indicating that DNA is a major inducer of lung IFN responses in infection. These results increase our understanding of this host-pathogen interaction and identify potential targets for host-directed therapies to reduce -mediated pathology.