FIG 2.

Differentiation of monocyte-derived human macrophages in fetal bovine serum versus human serum affects the outcome of Salmonella Typhimurium infection. Cells were cultured in media containing FBS or HuS for 7 days as described in the text and then infected with Salmonella WT strains SL1344 and14028. (A) Phase-contrast images of uninfected cells. Bar, 100 μm. (B) Gentamicin protection assay. Shown is the fold change in CFU (at 18 and 2 h p.i.). Results are means ± SD from 4 independent experiments. *, P < 0.05 by two-way ANOVA. (C) The percentages of infected cells containing <5, 5 to 9, or ≥10 bacteria were assessed by microscopy at 2 and 18 h p.i. Results are means ± SD from 4 independent experiments.