Figure 7. During the late intracellular phase, IglC and PdpA are necessary for efficient proliferation in lung epithelial cells.

Human A549 cells were infected by wild-type F. tularensis LVS, ΔiglC, ΔpdpA, ΔiglC::iglC and ΔpdpA::pdpA. Intracellular bacteria were enumerated at 24 and 48 h time-points using gentamicin protection assay. At 24 h PI, the sample was switched to a low gentamicin concentration (10 µg mL⁻¹) in order to inhibit growth of extracellular microbes. Intracellular bacteria were titred after they were released from host cells and serial diluted onto agar-containing media. Error bars, S.E.M (n = 3).