Listeria monocytogenes is a bacterial pathogen which replicates in the cytoplasm of infected cells. Cytosolic pattern recognition receptors (PRRs) respond to cytosolic bacterial products and contribute to the induction of the innate immune response [5, 6] . Previous studies in bone marrow-derived macrophages (BMM) and epithelial cells show that in these cell types the synthesis of IFN-I in response to infection with L. monocytogenes is independent of TLRs and their adapters, relying exclusively on signals originating from cytosolic sensors [5] [6] [7] [8] . DNA as well as cyclic dinucleotides released from lysed bacteria were suggested to function as the relevant L. monocytogenes PAMPs [9] [10] [11] . Several cytosolic proteins with the ability to sense pathogen-derived nucleic acids have recently been described [11] [12] [13] [14] [15] [16] [17] [18] [19] . Cytosolic recognition of L. monocytogenes causes the activation of the serine/threonine kinase TBK1 and the phosphorylation of its substrate transcription factors IRF3 and IRF7 [7, 8] . Both IRF3 and IRF7 participate in the formation of an enhanceosome at the IFN-b promoter [20] .