Mycobacterium tuberculosisinhibits autocrine type I interferon signaling to increase intracellular survival

Abstract

SummaryThe type I interferons (IFN-α and -β) are important for host defense against viral infections. In contrast, their role in defense against non-viral pathogens is more ambiguous. Here we report that IFN-β-signaling in macrophages has protective capacity against Mycobacterium tuberculosis (Mtb) via the increased production of nitric oxide. Furthermore, Mtb is able to inhibit IFN-α/β-receptor-mediated cell signaling and the transcription of 309 IFN-β stimulated genes which includes genes associated with innate host cell defense. The molecular mechanism of inhibition by Mtb involves reduced phosphorylation of the IFNAR-associated protein kinases JAK1 and TYK2 leading to reduced phosphorylation of the downstream targets STAT1 and STAT2. Overall, our study supports the novel concept that Mtb evolved to inhibit autocrine type I IFN signaling in order to evade host defense mechanisms.