FIGURE 3.

Heterogeneity in the number of intracellular bacteria occurs in primary human M-CSF-derived macrophages. Primary human M-CSF-derived macrophages derived from an otherwise healthy donor were infected with S. aureus after 7 days of differentiation. Macrophages are marked with TMR-WGA (in red) while S. aureus USA300 is expressing GFP (in green). At the outset of the infection bacteria were co-labeled with eFluor^TM-670 proliferation dye (pseudo-colored blue). These representative images were taken at 12 h post-infection and represent common events from multiple (>6) independent experiments. The white arrow head points to a primary phagocyte containing many cocci while the surrounding cells contain few. These bacteria are also marked with eFluor^TM-670 proliferation dye at this time-point. White arrows point to a phagocyte that contains many GFP-positive cocci that are eFluor^TM-negative indicating these bacteria have replicated. In contrast the surrounding cells contain few GFP-positive cocci that are also eFluor^TM-670-positive. Scale bar is ∼10 μm.