FIG. 3.

Effect of cytochalasin D pretreatment on iNOS and IRF-1 expression by LPS mutant- or wild-type-infected macrophages. To inhibit bacterial internalization, the macrophages were pretreated with cytochalasin D (2 μg/ml) for 2 h prior to the infection, and then the macrophages were infected with the bacteria at an MOI of 2:1 for 1 h. After 8 h of infection, the infected cells were lysed and the levels of iNOS, IRF-1, and actin were determined by immunoblotting. The results showed cytochalasin D to have no effect on the macrophage response.