Role of ICAM-1 and ICAM-2 and alternate CD11/CD18 ligands in neutrophil transendothelial migration.
We evaluated the relative contribution of ICAM-1 and ICAM-2, known ligands on endothelium for LFA-1 and Mac-1, in spontaneous neutrophil (PMN) transendothelial migration (TEM) across IL-1-activated HUVEC monolayers or TEM induced by C5a or IL-8 across unstimulated HUVEC grown on polycarbonate filters. Adhesion blocking mAb to ICAM-1 [R6.5 F(ab)2] or ICAM-2 [CBR IC2/2 F(ab)2] tended to inhibit TEM under each condition but, in general, inhibition was significant only with both ICAM-1 and ICAM-2 blockade. mAb to LFA-1 partially inhibited migration to C5a or IL-8 across unstimulated HUVEC and inhibition was not altered by additional treatment of HUVEC with mAbs to ICAM-1 and -2. In contrast, with IL-1 HUVEC, mAb to ICAM-1 significantly inhibited this LFA-1-independent TEM. mAb to Mac-1 alone partially inhibited TEM and, when combined with mAb to LFA-1, migration was almost completely blocked with all TEM conditions tested. The contribution of alternate ligands for Mac-1 in mediating Mac-1-dependent but ICAM-1/-2-independent C5a-induced TEM was examined using anti-LFA-1-treated PMN and anti-ICAM-treated resting HUVEC. Addition of RGD peptides, fibronectin, fibrinogen, heparins, collagens alone or in combination, even to heparinase-treated HUVEC, did not inhibit this Mac-1-mediated PMN TEM. The results indicate that: (1) LFA-1 mediates PMN TEM primarily by interaction with ICAM-1 and ICAM-2; (2) ICAM-2 may function in concert with ICAM-1 in this role, especially on unstimulated endothelium, and (3) Mac-1 on PMN also plays a major role in TEM and can utilize yet to be identified ligands distinct from ICAM-1 or -2, especially on unstimulated endothelium.
Issekutz
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Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, Canada. aissekutz@iwkgrace.ns.ca
Rowter
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Springer
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D000911:Antibodies, Monoclonal / Q000494:pharmacology; D015703:Antigens, CD / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D007375:Interleukin-1 / Q000494:pharmacology; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1 / Q000502:physiology*; D016177:Macrophage-1 Antigen / Q000502:physiology*; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D015815:Cell Adhesion Molecules; C065289:ICAM2 protein, human; D007375:Interleukin-1; D008024:Ligands; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D018799:Intercellular Adhesion Molecule-1