Fig 3.

Infection of macrophages and epithelial cells. (A) Infection of J774A.1 macrophages with the D39 WT and its ΔarcD, ΔarcT, and ΔarcDT mutants. Macrophages were infected at an MOI of 5:1. The CFU of the input and the intracellular (uptake) bacteria were enumerated by plating from serial dilutions. (B) Bacterial adherence to A549 epithelial cells. A549 epithelial cells were infected at an MOI of 50:1 with the D39 WT and its ΔarcD, ΔarcT, and ΔarcDT mutants. Input and cell-associated (adherence) bacteria were enumerated by plating from serial dilutions. (C) Complementation of the D39 ΔarcD mutant. Infection of A549 cells at an MOI of 50:1 with the D39 WT, the ΔarcD and ΔarcD (pST2605) mutants, and the empty vector control strain ΔarcD (pST2586). All the data shown are the means of three independent experiments. Error bars denote SEMs. *, P < 0.05; ***, P < 0.001.