c-di-AMP Secreted by Intracellular Listeria monocytogenes Activates a Host Type I Interferon Response

Abstract
Bacterial (Interferon)ce: Intracellular bacterial pathogens, such as Listeria monocytogenes , are detected in the cytosol of host immune cells, where they induce a host response that is often dependent on microbial secretion systems. Woodward et al. (p. 1703 , published online 27 May) now show that L. monocytogenes produce and release cyclic diadenosine monophosphate into the host cytosol, which induces the production of host type I interferon. Because a number of intracellular pathogens contain the protein machinery to generate this nucleotide and also activate this same innate immune pathway, a common molecular mechanism may exist for host detection of cytosolic bacterial pathogens.