FIG 5 .

A fluorescent-antibody internalization assay indicates that ExoS inhibits phagocytosis through an ADPRT-dependent mechanism. (A) Mice were infected with strain PA99null+S, PA99null, PA99null+S(R146A), or PA99null+S(E379A/E381A) for 24 h. Leukocytes were isolated from whole lungs and analyzed by flow cytometry to identify those with intracellular bacteria (CD45⁺ red⁺ green⁻). Each symbol represents the value for an individual mouse (15 mice per strain). Black bars indicate the medians for the groups of mice. The confidence intervals (CIs) of the medians (confidence levels shown in the parentheses) are as follows: 12.8 to 29.0 (98.71) for strain PA99null+S, 17.7 to 27.2 (98.71) for PA99null, 13.0 to 28.6 (96.48) for PA99null+S(R146A), and 17.0 to 27.5 (96.48) for PA99null+S(E379A/E381A). P = 0.05 (overall ANOVA). (B) Intracellular/extracellular bacteria were confirmed by viewing cell populations with a fluorescence microscope. The green arrow indicates an extracellular bacterium associated with a CD45⁺ cell sorted in the red⁺ green⁺ cell population; the red arrow indicates intracellular bacteria associated with a CD45⁺ cell sorted in the red⁺ green⁻ cell population.