FIG 1.

Analysis of PGE2 and IL-1β secretion in THP-1 macrophages infected with wild-type, ΔyopB, or heat-killed Y. enterocolitica and Y. pseudotuberculosis. PMA-differentiated THP-1 macrophages were infected at an MOI of 50:1 with wild type, ΔyopB Y. enterocolitica (Ye; A and B) and Y. pseudotuberculosis (Yptb; C and D) or treated with an equivalent number of heat-killed bacteria for 2 h. Uninfected macrophages were used as a control (Ctrl). Bacteria were heat killed at 55°C for 30 min before treating macrophages, and loss of viability was confirmed by plating. Commercial monoclonal ELISAs were used to measure the concentrations of PGE2 (A and C) and IL-1β (B and D) in supernatants from Y. enterocolitica- or Y. pseudotuberculosis-infected THP-1 cells. One-way ANOVA and Tukey’s post hoc test were used to calculate significance (n = 3). P values are indicated (*, P ≤ 0.05; **, P ≤ 0.01; ***, P ≤ 0.001; ****, P ≤ 0.0001). The data are representative of three independent experiments.