Migration of leukocytes through endothelium is impaired by blockage of PV-1 under flow. (A) Analysis of PV-1 expression on the surface of HUVECs. Cells were incubated with anti–PV-1 or 2 different isotype-matched negative control antibodies (3G6 or NS-1). (B) Cytochemical detection of PV-1 expression on the surface of HUVECs. A representative cell from the brightly stained population is depicted. Side views of a z-stack are shown from 2 different planes, indicated by colored lines in the small pictures on top and on the right. Small inset in the upper right corner represents negative control staining. Arrows point to a PV-1 pool on the surface. Nuclear counterstaining was performed with DAPI. (C) Analysis of rolling, adherent, and transmigrated PBMCs at the indicated time points using capillary flow assay. (D) Analysis of polymorphonuclear cell adhesion and transmigration under flow. The graphs represent mean ± SEM of 3 independent experiments using HUVECs and leukocytes from different individuals. Values of capillaries treated with negative control antibodies have been set as 100%.