JAM-A expression in the hepatic microvasculature. Immunostaining for JAM-A was performed in cryosections of the murine liver. (A) Under control conditions, JAM-A expression was found in cells localized in liver parenchyma (arrow), but not in vascular endothelial cells. Magnification, × 200 (objective 20×/0.5). (B) In the postischemic liver, JAM-A expression was strongly expressed in the vessel wall of hepatic venules (arrow). Magnification, × 200. (C) Examination of JAM-A staining at higher magnification (× 1000 oil immersion objective 100×/1.30) shows JAM-A positively stained endothelial cells (arrows indicate spindle-shaped nuclei of endothelial cells) as well as JAM-A-expressing adherent leukocytes in the liver after I/R (arrowhead). (D) In bile duct epithelial cells (arrow), postischemic JAM-A expression was very weak and hardly detectable. Magnification, × 1000 oil. (E) No JAM-A expression was detected in JAM-A^-/- mice after I/R. Magnification, × 200. (F) In postischemic livers of endothelial JAM-A^-/- mice, JAM-A expression was found only in parenchymal (arrow) but not in vascular endothelial (arrowhead) cells. Magnification, × 200.