(A) Human PMNs do not kill B. anthracis through superoxide generation. To determine if B. anthracis is killed by human PMNs through superoxide generation, vegetative bacteria were incubated with human PMNs alone at an MOI of 1:1 or in the presence of SOD to inhibit superoxide generation. Means and standard deviation of three different experiments are shown. (B) Western blot of NOS2 expression in human PMN and RAW macrophages with B. anthracis infection.