Figure 2.

Microbicidal activity of placental macrophages. Placental CD14⁺ macrophages (2 × 10⁶ cells per assay) were infected or not by C. burnetii (bacterium-to-cell ratio of 50:1) for 4 h. (A) Confocal pictures show placental macrophage infected of not by DID-labeled bacteria. Infected macrophages were illustrated by the sections at the top and the right of the image was bacteria indicated in red, F-actin labeled with phalloidin-488 in green, and nucleus stained with Hoechst 3342 in blue. (B) Placental macrophages were incubated with C. burnetii for 4 h (day 0), then washed to eliminate free bacteria and incubated for 9 days. Lactate dehydrogenase (LDH) quantification was performed at each time of kinetic time of infection (n = 4 placentas). (C) Pictures of placental macrophages infected by C. burnetii at 0-, 3-, 6- and 9-day post-infection. Bacteria are indicated in red, F-actin labeled with phalloidin-488 in green and nucleus stained with Hoechst 3342 in blue. (D) Every 3 days, the number of bacterial DNA copies was evaluated by qPCR (n = 14 placentas). **p ≤ 0.01 and ***p ≤ 0.001. (E) Percentage of live/dead bacteria number was evaluated per macrophages at each time (ns = not significant).