Fig. 3.

Reduction of NO levels in postactivated macrophages infected with pgm⁺ Y. pestis is not controlled at the level of iNOS expression. (A) BMM infected with KIM10+/GFP or KIM10/GFP were exposed to IFN-γ. Uninfected BMM were exposed to LPS and IFN-γ. Twenty-five hours after infection or LPS/IFN-γ exposure, the nitrite concentration in the supernatant of the macrophages was measured. Nitrite levels in infected cells were normalized relative to the nitrite levels in uninfected macrophages exposed to LPS/IFN-γ. Each bar represents the average of five infections from two independent experiments. (B) Uninfected BMM exposed to LPS, or BMM infected with KIM10+/GFP or KIM10/GFP, were incubated for 25 h in the presence or absence of IFN-γ. Lysates of the infected macrophages were analyzed by immunoblotting with an anti-iNOS antibody or with an anti-SKAP-HOM antiserum to control for loading.