Transcellular PMN transmigration through funnel-like indentations at the apical PCPEC membrane. (A-C) The TEM images are serial sections in parallel to the Transwell filter of TNFα-stimulated PCPEC monolayers with an interval of 2-3 μm between them. In the middle, we have the cross-sectioned funnel lined by a seam of microvilli and rare cilia of one cell. (A) basal body of a cilium is labelled by an arrow in (B), proving that this surface is the apical surface of the epithelial cell. In this figure, identical cell profiles in the different pictures are numbered correspondingly. Scale bar, as indicated.