FIG 4.

pHepc induced the downregulation of FPN and increased intracellular bacterial growth. (A and B) IPEC-1 enterocytes (A) or 3D4/2 macrophages (B) were infected with pHepc-treated S. Typhimurium bacteria for 1 h, and extracellular bacteria were washed away with PBS containing gentamicin. Cell lysates were then used to quantitate the intracellular bacteria for measurement of the number of CFU (expressed on the y axis as a ratio of the level for the control group). (C) Western blot analysis showing FPN protein levels in 3D4/2 cells. (D) The iron chelator DFO removes the iron stored in macrophages, limiting intracellular S. Typhimurium growth. 3D4/2 macrophages were infected with pHepc-treated S. Typhimurium for 1 h, extracellular bacteria were washed away, and cells were incubated in the presence of DFO for 4 h. Cells were processed for immunofluorescence, and the number of bacterial foci per cell was determined as described above. Experiments were repeated a minimum of 3 times. Error bars indicate SEs. *, P < 0.05.