Abstract
Circulating lymphocytes gain access to lymph nodes owing to their ability to initiate rolling along specialized high endothelial venules (HEVs). One mechanism of rolling involves L-selectin binding to peripheral node addressin (PNAd) on HEVs. Activated platelets are shown to bind to circulating lymphocytes and to mediate rolling in HEVs, in vivo, through another molecule, P-selectin, which also interacts with PNAd. In vitro, activated platelets enhanced tethering of lymphocytes to PNAd and sustained lymphocyte rolling, even in the absence of functional L-selectin. Thus, a platelet pathway operating through P-selectin provides a second mechanism for lymphocyte delivery to HEVs.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Antigens, Surface / metabolism*
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Blood Platelets / physiology*
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Cell Adhesion
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Cell Movement
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Endothelium, Vascular / cytology
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Humans
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L-Selectin / physiology
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Ligands
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Lymph Nodes / blood supply*
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Lymph Nodes / cytology
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Lymphocytes / cytology
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Lymphocytes / physiology*
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Membrane Glycoproteins / metabolism
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Membrane Proteins
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Mice
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P-Selectin / metabolism
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Platelet Activation
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Receptors, Lymphocyte Homing / metabolism
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Transfection
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Tumor Cells, Cultured
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Venules / cytology
Substances
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Antigens, Surface
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L-selectin counter-receptors
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Ligands
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Membrane Glycoproteins
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Membrane Proteins
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P-Selectin
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P-selectin ligand protein
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Receptors, Lymphocyte Homing
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L-Selectin