Indeed, in addition to triggering the innate Type I IFN driven Irg1 response studied here, in later infection Mtb through its induction of a strong Th1 dependent response can generate substantial levels of IFN-γ, a second major cytokine stimulus of Irg1, that should help sustain high level production of the enzyme beyond the acute phase of infection. Here, ACOD1 is linked to infection.