Locomotion of monocytes on endothelium is a critical step during extravasation.
Monocytes, like all leukocytes, undergo a series of sequential steps during extravasation from blood into tissues: tethering, rolling, adhesion and diapedesis. We have discovered an essential step, which we call locomotion, in which the monocyte moves from a site of firm adhesion to the nearest junction to begin diapedesis. Blocking CD11a-CD18 and CD11b-CD18 on human monocytes or adhesion molecules ICAM-1 and ICAM-2 on endothelial cells prevented the monocytes from reaching junctions. The blocked monocytes spun in circles as if they were unable to direct their movement despite being able to adhere and polarize normally. This step fills a gap in the paradigm of extravasation as a multistep process.
Schenkel
Alan R
AR
Department of Pathology, Weill Medical College of Cornell University, Room C320, 1300 York Avenue, New York, New York 10021, USA. als2015@med.cornell.edu
Mamdouh
Zahra
Z
Muller
William A
WA
D015703:Antigens, CD / Q000378:metabolism; D018821:CD18 Antigens / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D009000:Monocytes / Q000502:physiology*; D014471:Umbilical Veins / Q000502:physiology
D015703:Antigens, CD; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; C065289:ICAM2 protein, human; D018799:Intercellular Adhesion Molecule-1