(a) Effect chlamydial infection on monocyte recruitment to endothelium. 106 monocytes/mL was perfused over confluent HAECs activated with uninfected or infected monocyte supernatant at a wall shear stress of 1 dyn/cm2. After 1 min of perfusion, the interactions were captured by bright-field microscopy at 20× magnification for 4 min in 5 different fields of view (0.1 × 0.1 mm2). The results are expressed as mean ± SD of one representative experiment performed in triplicate, and the experiments were performed two times. The * represent statistically significant change (p<0.05, Student's t test) in monocyte adhesion due to infection compared to uninfected control. (b) Effect of infection and shear stress on monocyte chemotaxis. Supernatants from experiments described in Fig. 3 were diluted 3-fold, added to the lower portion of the Boyden chamber. Fresh, uninfected THP1 cells at a density of 5 × 106 cells/mL were added to the top portion of the Boyden chamber with 5 μm pore-filter. The setup was incubated for 2 h at 37 °C, and the number of cells transmigrated through the pore to the bottom of the well were counted. The results are expressed as mean ± SD of the number of transmigrated cells per μL of suspension in the lower well from one representative experiment performed in triplicate, and the experiments were performed three times. The * and § represent statistically significant change (p<0.05, ANOVA) in monocyte migration by due to infection only under static conditions, or due to shear stress only in infected cells compared to respective controls.