FIGURE 4.

Effect of PGE2 on bacterial load during infection with Salmonella Typhimurium or Yersinia enterocolitica. THP-1 macrophages (2.5 × 10⁵) were infected with (A) wild-type Salmonella or (B), (C) wild-type Yersinia (MOI of 50:1) in the presence or absence of PGE2. At the indicated times post-infection, macrophages were lysed with 0.1% Triton-X, diluted, and dilutions were plated on LB agar plates. A dose–response curve was generated by pretreating THP-1 macrophages with varying concentrations of PGE2 before infection with Y. enterocolitica, and then the resulting CFUs were measured 2 hpi (C). Similarly to (B), uptake and survival of Y. enterocolitica in HeLa cells was also evaluated (D). Results are represented as the mean ± SD of at least three identical wells across three independent experiments. Significance denoted by ^∗ was calculated using Student’s t-test with p < 0.05. p-values were indicated as follows: ^∗p ≤ 0.05; ^∗∗p ≤ 0.01; ^∗∗∗p ≤ 0.001; ^∗∗∗∗p ≤ 0.0001.