Clearance of Shigella flexneri Infection Occurs through a Nitric Oxide-Independent Mechanism

Nitric oxide (NO) generated by gamma interferon (IFN-γ) activation of macrophages mediates the killing of many intracellular pathogens. IFN-γ is essential to innate resistance to Shigella flexneri infection. We demonstrate that NO is produced following S. flexneri infection both in mice and in activated cells in vitro and that while it is able to kill S. flexneri in a cell-free system, it is not required for clearance of S. flexneri in either infected mice or in activated cells in vitro.