Differential signaling of inducible nitric oxide synthase induction in Mycobacterium tuberculosis infected alveolar epithelial cell line A549 in response to cytokines IFN-γ, TNF-α and IL-1β

In earlier studies, it was shown that ex vivo Mycobacterium tuberculosis-infected type II alveolar epithelial cells generate de novo nitric oxide (NO), but the mycobactericidal quantity of NO was released only by stimulation of these cells with proinflammatory cytokines, i.e. IFN-γ, TNF-α and IL-1β. In the present communication, it was demonstrated that M. tuberculosis-infected/mycobacterial antigens stimulated cells utilize both, JAK-STAT and NF-κB pathways for the induction of inducible Nitric Oxide Synthase (iNOS) mRNA and NO production.