FIGURE 2.

In vitro killing of Listeria by macrophages. TPMs were cultured overnight with either IFN-γ (filled triangle, ACE 10/10; filled circle, WT) or without IFN-γ priming (open triangle, ACE 10/10; open circle, WT). At time 0, cells were infected with Listeria at a multiplicity of 10 for 1 h. Then, after washing, medium containing gentamicin was added to kill the remaining extracellular bacteria. After further incubation, such that the total time since first exposure to bacteria was 2 to 8 h, the antibiotic was removed, the cells were lysed, and cfus were determined. In the presence of IFN-γ priming, there is substantially better killing of Listeria by ACE 10/10 macrophages than by WT cells (n = 8 mice). **, p < 0.005; ***, p < 0.001.