CLEVER-1 is involved in PBMC transmigration through lymphatic endothelium. (A) PBMCs were allowed to adhere and transmigrate through a confluent monolayer of lymphatic endothelium under static conditions (see “Materials and methods”). In the micrograph, 2 transmigrated cells (solid white arrows; phase dark) and 3 surface adherent cells (white open arrows; phase bright; the level of brightness depending on the extent of flattening of the adherent cells) are shown. Bar, 10 μm. (B) The numbers of adherent and transmigrated cells were then enumerated from video playbacks after different mAb pretreatments. The results are expressed as percentage of binding when compared with control mAb (a binding mAb against HLA class I, which does not block PBMC adherence). The results are mean ± SEM from 5 independent experiments.