title: Molecular events during leukocyte diapedesis.
abstract: The recruitment of leukocytes from the circulation into tissues requires leukocyte migration through the vascular endothelium. The mechanisms by which leukocytes attach and firmly adhere to the endothelial cell surface have been studied in detail. However, much less is known about the last step in this process, the diapedesis of leukocytes through the vascular endothelium. This minireview focuses on the interactions between leukocyte and endothelial cell adhesion molecules that are important during leukocyte extravasation. In the past few years a series of endothelial cell surface and adhesion molecules have been identified that are located at endothelial cell contacts and found to participate in leukocyte diapedesis. These junctional cell adhesion molecules are believed to have an active role in controlling the opening and closure of endothelial cell contacts to allow the passage of leukocytes between adjacent endothelial cells. Alternatively, leukocytes can cross the endothelium at nonjunctional locations, with leukocytes migrating through a single endothelial cell. Further work is clearly needed to understand, in greater detail, the molecular mechanisms that allow leukocytes to cross the endothelium via either the paracellular or the transcellular pathway.
authors.affiliation: Max-Planck-Institute of Molecular Biomedicine, Münster, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Petri
authors.forename: M Gabriele
authors.initials: MG
authors.lastname: Bixel
mesh_terms: D000071443:12E7 Antigen; D000818:Animals; D015703:Antigens, CD / Q000502:physiology; D002199:Capillary Permeability; D015815:Cell Adhesion Molecules / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D042783:Endothelial Cells / Q000502:physiology*; D006801:Humans; D007136:Immunoglobulins / Q000502:physiology; D007962:Leukocytes / Q000502:physiology*; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000502:physiology; D011956:Receptors, Cell Surface; D019010:Vascular Cell Adhesion Molecule-1 / Q000502:physiology
chemical_list: D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; C428190:Esam protein, mouse; C407243:F11R protein, human; D007136:Immunoglobulins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011956:Receptors, Cell Surface; D019010:Vascular Cell Adhesion Molecule-1