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Query: UMLS:C0001511 (Adhesion)
 5,955 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the adhesion of human peripheral blood T lymphocytes to human synovial fibroblasts stimulated with interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), interleukin-1 beta (IL-1 beta), or combinations of these cytokines. T lymphocytes bound poorly to untreated human synovial fibroblasts. IFN gamma treatment resulted in the largest increase in adhesion, followed by TNF alpha and IL-1 beta. Combinations of IFN gamma + TNF alpha and IFN gamma + IL-1 beta had a synergistic effect on intercellular adhesion molecule 1 (ICAM-1) expression and adhesion. The increase in cellular adhesion induced by cytokines correlated with the up-regulation of the number of cells expressing ICAM-1 and the density of antigen/cell. There was no synergistic effect on leukocyte function-associated antigen 3 (LFA-3) or on HLA class I or class II antigen expression. Adhesion was only partially inhibited by anti-ICAM-1, anti-LFA-1, or anti-CD18. These findings suggest the existence of ICAM-1--independent and CD11/CD18-independent adhesion mechanisms. Anti-LFA-3 was completely ineffective as an inhibitor of adhesion. There was no additive or synergistic advantage of using combinations of antibodies to increase the level of inhibition, i.e., anti--ICAM-1 + anti-LFA-3, anti-ICAM-1 + anti-CD18, or anti-ICAM-1 + anti-LFA-1 (CD11a). Our data indicate that proinflammatory cytokines may play a prominent role in the formation and exacerbation of synovial hyperplasia, by regulating the recruitment and retention of T lymphocytes via the up-regulation of adhesion molecules on synovial fibroblasts.
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PMID:T lymphocyte adhesion to human synovial fibroblasts. Role of cytokines and the interaction between intercellular adhesion molecule 1 and CD11a/CD18. 168 12

Adhesion of activated leukocytes to cells is of critical functional importance. The adhesion is known to be mediated mainly by the CD11/CD18 integrins, also known as leukocytic cell adhesion molecules, or Leu-CAM. We have now studied the phosphorylation of Leu-CAM by protein kinase C and the correlation of phosphorylation with the generation of the adhesive phenotype among human peripheral blood mononuclear leukocytes during cell activation. We here show that a good correlation exists between the phosphorylation of the beta subunit of Leu-CAM (CD18), and the extent of cell-to-cell adhesion. The phosphorylated CD18 subunit was associated with both CD11a and CD11b. Purified protein kinase C was able to phosphorylate the beta subunit of isolated Leu-CAM in vitro. The phosphorylation occurred mainly on serine residues.
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PMID:Phosphorylation of the beta-subunit of CD11/CD18 integrins by protein kinase C correlates with leukocyte adhesion. 168 56

Adhesion of hematopoietic cells to endothelial (En) cells plays an important role in their migration into extravascular tissue. This report characterizes the adhesion properties of naive splenocytes to syngeneic and allogeneic mouse brain microvascular endothelium isolated from the BALB/c or SJL/j mouse strains. Syngeneic adhesion reaches maximum levels by 60 min at 37 degrees C, but is more pronounced in the BALB/c system (mean adhesion = 10.7% +/- 1.0) compared to adhesion seen in the SJL/j (mean adhesion = 4.3% +/- 0.6). BALB/c, but not SJL/j adhesion, seems to be mediated, at least in part, by the interaction of CD11a/CD18 (lymphocyte function-associated antigen 1 (LFA-1] with one of its ligands, because BALB/c adhesion is partially inhibited when the assay is carried out either in the presence of chelating agents or with antibodies to the CD11a/CD18 molecule. Activation of the endothelium with recombinant interferon-gamma (rIFN-gamma), recombinant interleukin-1 alpha (rIL-1 alpha), and recombinant tumor necrosis factor-alpha (rTNF-alpha), enhances adhesion in both BALB/c and SJL/j. IFN-gamma and IL-1 alpha mediated adhesion enhancement is abrogated by antibodies to the CD11a/CD18 molecules in the BALB/c but not in the SJL/j system. The adhesion of splenocytes to mouse brain En clearly has unique properties, and whether or not the differences seen in the SJL/j system in any way influences its susceptibility to the autoimmune demyelinating disease, experimental autoimmune encephalitis, remains to be determined.
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PMID:Adhesion of splenocytes to brain microvascular endothelium in the BALB/c and SJL/j mouse systems. 168 52

The overall objective of this study was to determine whether leukocyte adherence and/or emigration is a prerequisite for the increased vascular protein leakage associated with acute inflammation. An in vivo preparation was used to monitor intestinal vascular protein leakage as well as polymorphonuclear leukocyte (PMN) adhesion and emigration in feline mesenteric microvessels exposed to platelet-activating factor (PAF) and leukotriene B4 (LTB4). Local intra-arterial infusion of PAF (4 ng/min) produced a fourfold increase in vascular protein leakage. A 50-fold higher concentration of LTB4 had no effect on vascular protein efflux. LTB4, however, did potentiate the PAF-induced vascular protein leakage. Both inflammatory mediators caused leukocytes to adhere to endothelial cells in postcapillary venules; however, leukocyte emigration was observed only in the presence of PAF. PAF-induced leukocyte adhesion and emigration and the increased vascular protein leakage were inhibited by a monoclonal antibody (MoAb IB4) directed against the common beta-subunit of the adhesive glycoprotein complex CD11/CD18. MoAb IB4 also prevented LTB4-induced leukocyte adhesion. Both PAF and LTB4 caused degranulation of cat PMNs in vitro, yet superoxide production was stimulated by PAF only. The data derived from these in vivo and in vitro studies indicate that leukocyte adhesion per se does not necessarily lead to increased vascular protein leakage and leukocyte emigration. Adhesion-dependent PMN functions such as emigration and superoxide production may play an important role in producing the alterations in vascular integrity observed in inflamed microvessels.
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PMID:Leukocyte-induced vascular protein leakage in cat mesentery. 168 68

Activation of human umbilical vein endothelial (HUVE) cells with the inflammatory mediators tumour necrosis factor-alpha (TNF), interleukin-1 (IL-1), lipopolysaccharide (LPS) and phorbol esters enhanced their adhesiveness for leucocytes. The appearance of an activation antigen ELAM-1, recognized by a monoclonal antibody (MoAb) ENA1, parallels the kinetics of the enhanced adherence of leucocytes to endothelial cells. Adhesion of polymorphonuclear cells (PMN) to activated HUVE cells could be blocked by F(ab')2 fragments of MoAb ENA1 up to 60%. An additive inhibition of the adhesion was established by pre-incubation of the PMN with anti-CD18 MoAb and/or leucocyte adhesion inhibitor (LAI), produced by endothelial cells. An opposite reaction, however, was observed when HUVE cells were pre-incubated with intact MoAb ENA1, resulting in an enhancement of the adhesion up to 200%. Apparently, the blocking effect of MoAb ENA1 could be bypassed by the strong interaction of the Fc part of the MoAb with the Fc receptor (FcR) on the PMN. Similarly, anti-CD18 MoAb and/or LAI reduced the adhesion observed if intact ENA1 were used, and Fc-FcR interaction took place. The results presented in this study indicate that adhesion via ELAM-1, the CD18 antigen and via the receptor for LAI are different mechanisms. These mechanisms may act in concert to strengthen the binding of PMN to HUVE cells. Moreover, a strong adhesion could be established via the Fc part of MoAbs directed against HUVE cells with the FcR on the PMN. The phenomenon described may play a role in graft rejection and in diseases where antibodies directed against endothelium are involved.
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PMID:Adhesion of polymorphonuclear cells to human endothelial cells. Adhesion-molecule-dependent, and Fc receptor-mediated adhesion-molecule-independent mechanisms. 169

We examined the actions of tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1 beta) on neutrophil and monocyte (phagocyte) adhesion to human mesangial cell monolayers (HMC) and assessed the role of phagocyte CD11/CD18 integrin adhesion molecules and HMC intercellular adhesion molecule-1 (ICAM-1) in this process, using subunit specific monoclonal antibodies (MAb). TNF, but not IL-1, provoked rapid (onset less than 1 min) neutrophil and monocyte adhesion to HMC by a phagocyte-directed action. Adhesion was markedly inhibited by MAb against CD18 and CD11b, with lesser or no inhibition being afforded by MAb against CD11a, CD11c, or ICAM-1. In contrast, prolonged exposure of HMC to TNF or IL-1 (1-18 h) increased HMC adhesiveness for phagocytes. These actions were blocked by actinomycin D or cycloheximide and by MAb against HMC ICAM-1 or phagocyte CD18, CD11a, or CD11b, suggesting that cytokines provoked adhesion by inducing HMC ICAM-1 synthesis. In keeping with this interpretation, TNF treatment of HMC was associated with increased ICAM-1 surface expression, as determined by indirect immunofluorescence, and increased ICAM-1 mRNA levels, as determined by Northern blot analysis. The actions of TNF on phagocytes and HMC were additive. HMC injury, as determined by 51Cr release, was only observed when both phagocytes and HMC were activated by TNF. HMC injury was attenuated by anti-CD18 MAb and superoxide dismutase, suggesting that the injury process was, in part, adhesion dependent and mediated by reactive oxygen species.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cytokine-induced phagocyte adhesion to human mesangial cells: role of CD11/CD18 integrins and ICAM-1. 172 95

During their life span, leukocytes adhere transiently to one another, to other cell types, such as vascular endothelial cells, and to extracellular matrix proteins. This adhesiveness is mediated by families of specific cell surface adhesion molecules, namely, integrins, immunoglobulin superfamily molecules, and selectins. Adhesion is required for leukocyte-mediated cytotoxicity, phagocytosis, chemotaxis, and induction of lymphocyte proliferation and maturation. It also participates in recirculation and homing of lymphocytes into lymphoid organs and in leukocyte migration from the vascular compartment to extravascular tissues. Adhesion underlies the beneficial or detrimental role of leukocytes in immune and inflammatory responses. In animals, blocking monoclonal antibodies to adhesion molecules dramatically reduce vascular and tissue injury in several organs following ischemia-reperfusion, and delay renal allograft rejection. Moreover, expression of particular adhesion molecules is induced or increased in cells which are targets for allergic or autoimmune reactions and in inflamed tissues. On the other hand, a congenital deficiency of the CD11/CD18 integrins (Leu-CAMs) leads to recurrent, and sometimes fatal, bacterial infections, and lack of particular cell-adhesion molecules on Burkitt's lymphoma cells may enable these cells to escape immunosurveillance.
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PMID:Leukocyte adhesion in host defense and tissue injury. 183 Aug 30

Although the in vivo interaction between polymorphonuclear neutrophils (PMN) and fibroblasts may be important, these pathways have not been well studied. We have investigated the adherence of PMN to monolayers of human fetal lung fibroblasts, using a microtiter plate assay based upon the uptake by cells of the vital stain Rose Bengal. Stimulation with phorbol myristate acetate (PMA) caused a significant increase of adherence over basal levels which was rapid in onset and plateaued at 5 min. Adhesion was dependent on the leucocyte integrin family of glycoproteins, notably on Mac-1, since monoclonal antibodies toward the beta chain (CD18) and alpha chain (CD11b) of Mac-1 almost completely suppressed PMA-induced PMN adhesion (88% and 77% inhibition, respectively). Adhesion was also inhibited by the peptides RGDS and GRGDS (24.2% and 26.6%, respectively using 1 mM peptide). Prestimulation of fibroblasts for longer time periods (5 and 24 h) with interleukin 1 alpha and tumor necrosis factor alpha, but not transforming growth factor beta, also resulted in a significant increase in adhesion of unstimulated PMN (after 24 h preincubation, 10 U/ml IL1 alpha stimulated adhesion by 179% of control, 500 U/ml TNF alpha by 157%). This indicated that there are both PMN- and fibroblast-dependent pathways for PMN adhesion. Components of the extracellular matrix of fibroblasts do not appear to play important roles in the adhesion process since addition of fibronectin and type IV collagen, or of purified antibodies to fibronectin and types I and IV collagen, did not affect PMA-induced PMN adhesion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Adhesive interactions between fibroblasts and polymorphonuclear neutrophils in vitro. 187 35

Culture of human monocyte-depleted peripheral blood mononuclear cells with recombinant IL2 (rIL2) induced adherence to plastic by 24 hr and subsequent proliferation in a subpopulation of lymphocytes with phenotypic and functional characteristics of activated natural killer (NK) cells. Purified human NK cells activated in the presence of IL2 for 24 hr upregulated the expression of the CD11c (p150.95) and CD11a antigen but not other cellular adhesion molecules (CAM). After further incubation with IL2, NK cells displayed upregulation of all of the antigens in the CD11/CD18 family of CAM. The process of adhesion was strictly dependent on culture in the presence of IL2, divalent cations, and active cellular metabolism. Adhesion also was dependent on expression of CAM on the cell surface, since monoclonal antibodies to CAM inhibited adhesion of activated NK cells to varying degrees (from 50 to 80%). An antibody (LeuM5) to the CD11c antigen (p150.95) gave the highest level of inhibition, and anti-CD11a (LFA-1) also was inhibitory, while anti-CD56 (NKH1) or anti-CD11b did not interfere with adhesion to plastic. Anti-CD11c was also the most effective in initiating the detachment of adherent-phase NK cells. Antibodies to CD18 or CD2 antigen also inhibited binding of NK cells to plastic. The blocking effects of anti-CD2 and anti-CD11a were additive in this system. On the surface of plastic-adherent and motile NK cells, all CAM except the CD56 antigen had a polar or bipolar distribution, as determined by staining with anti-CAM antibodies. Surface antigens CD11b, CD11c, CD2, and CD18 on nonadherent NK cells were clustered at the cellular poles by both immunofluorescence and immunogold electron microscopy, whereas CD11a (LFA-1) and CD56 antigens were distributed diffusely. CAM, especially CD11c, were also detected in cytoplasmic granules by immunostaining in IL2-activated NK cells. Thus, CAM may be stored in granules, allowing for their rapid transfer to the cell membrane in response to activation. Our results indicate that CAM are upregulated in IL2-activated NK cells and that some of these molecules (e.g., CD11c) play an important role in the development of plastic adherence by a subpopulation of these cells.
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PMID:Adhesion characteristics of human interleukin 2-activated natural killer cells. 190 85

Leukocyte-cell adhesion is a form of physical contact characterized by fast (firm) stickiness between the cells. To analyze the biology and molecular basis of this process, an adhesion-specific assay was developed: the phorbol ester-induced aggregation of human lymphocytes. This rapid and antigen-independent intercellular adhesion requires cellular metabolism, an intact cytoskeleton and extracellular divalent cations, and is mediated by preformed cell-surface proteins referred to as CAMs. Phorbol ester also induces aggregation of monocytes and granulocytes, as well as adhesion of T lymphocytes to either B cells or monocytes and of the leukocytes to vascular endothelial cells. By using the adhesion-specific assay and blocking monoclonal antibodies, several CAMs have been identified, namely the Leu-CAM family (CD11a-c/CD18) and ICAM-1 (CD54). The Leu-CAM family is composed of Leu-CAMa (CD11a/CD18), Leu-CAMb (CD11b/CD18) and Leu-CAMc (CD11c/CD18), three glycoprotein heterodimers made of a common beta-chain and distinct alpha-chains. ICAM-1 is an adhesive ligand for Leu-CAMa. Expression and use of the various CAMs is selective in different types of leukocytes. The Leu-CAMs have been purified and partially characterized. CD18, whose gene is on human chromosome 21, contains 5-6 N-linked complex-type oligosaccharides, and CD11 binds Ca++. Another adhesion pathway is mediated by CD2 and CD58. CD2, a glycoprotein selectively expressed by T cells, is a receptor for CD58, a cell-surface adhesive ligand with broad tissue distribution. Antibodies to the latter CAMs do not block the phorbol ester-induced lymphocyte aggregation. Adhesion is involved in a large variety of leukocyte functions. Anti-Leu-CAM antibodies block induction of IL-2 production and lymphocyte proliferation. Lymphocyte-mediated cytotoxicity is also inhibited. Endogenous NK and LAK cells use Leu-CAMs, ICAM-1 and CD2, and sometimes RGD receptors, to bind and kill tumor cells. Endogenous compounds such as H2O2 and LTB4 also induce Leu-CAM-dependent adhesion in monocytoid cells and granulocytes, respectively, and degranulation of the latter cells is enhanced by the adhesion process. Homologous CAMs have been identified in rabbit and mouse. In in vivo studies in the former species, anti-Leu-CAM antibodies block adhesion of leukocytes to vascular endothelium and thereby their migration into extravascular tissues. The antibodies thus inhibit granulocyte accumulation and plasma leakage in inflammatory lesions, and induce lympho- and granulocytosis, indicating that cell-adhesion contributes to the distribution of leukocytes in the body.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Leukocyte-cell adhesion: a molecular process fundamental in leukocyte physiology. 197 8


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