S. suis and TNFα alter the morphology of the tight junction protein ZO-1 and induce actin stress fiber formation after the transmigration of PMNs across PCPECs. (A-P) En face Apotome® microscopy of (A-D) control, (E-H) S. suis strain 10, (I-L) strain 10 Δcps and (M-P) TNFα-stimulated PCPEC monolayers stained for ZO-1 (red), actin (phalloidin, green) and nuclei (DAPI, blue) after PMN (yellow) transmigration. Top and side of each panel is a cross section through the z-plane of multiple optical slices. S. suis and TNFα-stimulated PCPECs showed an altered tight junction morphology and increased actin stress fiber formation. This figure is a representative example of three independent experiments that all gave similar results. Scale bar, 10 μm.