FOCI contain numerous dead cells.

<p>Mice were infected with PA99Sbla or strains secreting enzymatically inactive ExoS for 23 hr. The entire lung was incubated with a mixture of CCF2-AM and a dead cell stain and imaged with the TissueFAXS system. A) A focus of injected cells (blue) showing numerous dead cells (red) from a PA99Sbla-infected mouser. Scale bar represents 50 μm. B) For each lung lobe section, the proportions of dead cells among total ExoS-injected and total uninjected cells were counted. Data represent the average of at least 5 lobes pooled from 3 separate mice. Error bars represent standard deviations. (*, p < 0.05). C) A corresponding focus from the lungs of a mouse infected with PA99S(E379A/E381A)bla. Scale bar represents 50 μm.