Macrophage-Derived Cell Lines Do Not Express Proinflammatory Cytokines after Exposure to Bacillus anthracis Lethal Toxin

We present evidence that Bacillus anthracis lethal toxin (LT) suppresses rather than induces proinflammatory cytokine production in macrophages. Suppression is observed with extremely low levels of LT and involves inhibition of transcription of cytokine messenger RNA. Thus, LT may contribute to anthrax pathogenesis by suppressing the inflammatory response.