Biomedical subjects

D Vestweber

Publications and source records attributed to D Vestweber.

At least 55 records · Page 3Linked to original sources

PubMed1997

The P-selectin glycoprotein ligand-1 is important for recruitment of neutrophils into inflamed mouse peritoneum.

The P-selectin glycoprotein ligand-1 (PSGL-1) is a high-affinity ligand of P-selectin on myeloid cells and certain subsets of lymphoid cells. We generated the rat monoclonal antibody (MoAb) 2PH1 that recognizes an epitope within the first 19 amino acids at the N-terminus of the processed form of mouse PSGL-1. This antibody blocks attachment of mouse myeloid cells to P-selectin under both static and flow conditions. Intravenous administration of saturating amounts of 2PH1 reduced the number of rolling leukocytes in venules of the acutely exposed mouse cremaster muscle by 79% (+/-5.7%), whereas an anti-P-selectin MoAb reduced it completely. Examining the effect of the MoAb 2PH1 on the recruitment of neutrophils into chemically inflamed mouse peritoneum showed that blocking PSGL-1 inhibited neutrophil accumulation in the peritoneum by 82% (+/-7%) at 2 hours and by 59% (+/-7.9%) at 4 hours after stimulation. A similar effect was seen with the MoAb against P-selectin. Simultaneous administration of both antibodies at the 4-hour time point blocked neutrophil accumulation by 86% (+/-4.2%), arguing for an additional partner molecule for PSGL-1 besides P-selectin. This is the first demonstration of the importance of PSGL-1 in the recruitment of mouse neutrophils into inflamed tissue.

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PubMed1997

CD24, a mucin-type glycoprotein, is a ligand for P-selectin on human tumor cells.

P-selectin (CD62P) is a Ca2+-dependent endogenous lectin that can be expressed by vascular endothelium and platelets. The major ligand for P-selectin on leukocytes is P-selectin glycoprotein ligand-1 (PSGL-1). P-selectin can also bind to carcinoma cells, but the nature of the ligand(s) on these cells is unknown. Here we investigated the P-selectin binding to a breast and a small cell lung carcinoma cell line that are negative for PSGL-1. We report that CD24, a mucin-type glycosylphosphatidylinositol-linked cell surface molecule on human neutrophils, pre B lymphocytes, and many tumors can promote binding to P-selectin. Latex beads coated with purified CD24 from the two carcinoma cell lines but also neutrophils could bind specifically to P-selectin-IgG. The binding was dependent on divalent cations and was abolished by treatment with O-sialoglycoprotein endopeptidase but not endoglycosidase F or sialidase. The beads were stained with a monoclonal antibody (MoAb) to CD57 (HNK-1 carbohydrate epitope) but did not react with MoAbs against the sialylLe(x/a) epitope. The carcinoma cells and CD24-beads derived from these cells could bind to activated platelets or P-selectin transfected Chinese hamster ovary cells (P-CHO) in a P-selectin-dependent manner and this binding was blocked by soluble CD24. Transfection of human adenocarcinoma cells with CD24 enhanced the P-selectin-dependent binding to activated platelets. Treatment of the carcinoma cells or the CD24 transfectant with phosphatidylinositol-specific phospholipase C reduced CD24 expression and P-selectin-IgG binding concomitantly. These results establish a role of CD24 as a novel ligand for P-selectin on tumor cells. The CD24/P-selectin binding pathway could be important in the dissimination of tumor cells by facilitating the interaction with platelets or endothelial cells.

Amino Acid Sequence↗

PubMed1997

Differential effect of E-selectin antibodies on neutrophil rolling and recruitment to inflammatory sites.

The selectins are inducible adhesion molecules critically important for the inflammatory response. We investigate here the functional effects of three monoclonal antibodies (MoAbs) raised against murine E-selectin (9A9, 10E6, and 10E9.6) on neutrophil recruitment in vivo, leukocyte rolling and circulating leukocyte concentrations in vivo, and adhesion of myeloid cells to E-selectin transfectants and recombinant E-selectin-IgG fusion protein in vitro. MoAbs 9A9 and 10E6 map to the lectin and epidermal growth factor (EGF)-like domains of murine E-selectin, whereas 10E9.6 binds to the consensus repeat region. 10E9.6 blocked neutrophil recruitment in a model of thioglycollate-induced peritonitis in Balb/c mice by more than 90% but had no effect in C57BL/6 mice. 9A9 and 10E6 blocked neutrophil recruitment in this assay only when combined with a P-selectin antibody, 5H1. Neither 9A9 nor 10E9.6 alone blocked leukocyte rolling in tumor necrosis factor-alpha-treated venules of Balb/c mice, but 9A9 almost completely inhibited leukocyte rolling when combined with the function-blocking murine P-selectin MoAb, RB40.34. In contrast, 10E9.6 had no effect on leukocyte rolling in RB40.34-treated Balb/c or C57BL/6 mice. 10E9.6 did not affect adhesion of myeloid cells to E-selectin transfectants or attachment, rolling, and detachment of myeloid cells to murine E-selectin-IgG fusion protein. However, adhesion was completely blocked in the same assays by 9A9. Taken together, these results indicate that E-selectin serves a function, other than rolling, that appears to be critically important for neutrophil recruitment to inflammatory sites in Balb/c mice.

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PubMed1997

L-selectin from human, but not from mouse neutrophils binds directly to E-selectin.

L-Selectin on neutrophils as well as inducible E- and P-selectin on endothelium are involved in the recruitment of neutrophils into inflamed tissue. Based on cell attachment assays, L-selectin was suggested to function as a carbohydrate presenting ligand for E- and P-selectin. However, previous affinity isolation experiments with an E-selectin-Ig fusion protein had failed to detect L-selectin among the isolated E-selectin ligands from mouse neutrophils. We show here that L-selectin from human neutrophils, in contrast to mouse neutrophils, can be affinity-isolated as a major ligand from total cell extracts using E-selectin-Ig as affinity probe. Binding of human L-selectin to E-selectin was direct, since purified L-selectin could be reprecipitated with E-selectin-Ig. Recognition of L-selectin was abolished by sialidase-treatment, required Ca2+, and was resistant to treatment with endoglycosidase F. Binding of L-selectin to a P-selectin-Ig fusion protein was not observed. In agreement with the biochemical data, the anti-L-selectin mAb DREG56 inhibited rolling of human neutrophils on immobilized E-selectin-Ig but not on P-selectin-Ig. No such inhibitory effect was seen with the anti-mouse L-selectin mAb MEL14 on mouse neutrophils. Rolling of E-selectin transfectants on purified and immobilized human L-selectin was inhibited by mAb DREG56. We conclude that L-selectin on human neutrophils is a major glycoprotein ligand among very few glycoproteins that can be isolated by an E-selectin affinity matrix. The clear difference between human and mouse L-selectin suggests that E-selectin-binding carbohydrate moieties are attached to different protein scaffolds in different species.

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PubMed1997

P-selectin glycoprotein ligand-1 (PSGL-1) on T helper 1 but not on T helper 2 cells binds to P-selectin and supports migration into inflamed skin.

We have shown recently that mouse Th1 cells but not Th2 cells are selectively recruited into inflamed sites of a delayed-type hypersensitivity (DTH) reaction of the skin. This migration was blocked by monoclonal antibodies (mAb) against P- and E-selectin. Here we show that Th1 cells bind to P-selectin via the P-selectin glycoprotein ligand-1 (PSGL-1). This is the only glycoprotein ligand that was detectable by affinity isolation with a P-selectin-Ig fusion protein. Binding of Th1 cells to P-selectin, as analyzed by flow cytometry and in cell adhesion assays, was completely blocked by antibodies against PSGL-1. The same antibodies blocked partially the migration of Th1 cells into cutaneous DTH reactions. This blocking activity, in combination with that of a mAb against E-selectin, was additive. PSGL-1 on Th2 cells, although expressed at similar levels as on Th1 cells, did not support binding to P-selectin. Thus, the P-selectin-binding form of PSGL-1 distinguishes Th1 cells from Th2 cells. Furthermore, PSGL-1 is relevant for the entry of Th1 cells into inflamed areas of the skin. This is the first demonstration for the importance of PSGL-1 for mouse leukocyte recruitment in vivo.

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PubMed1997

P- and E-selectin mediate recruitment of T-helper-1 but not T-helper-2 cells into inflammed tissues.

When activated, T helper cells differentiate into one of two subsets, Th1 and Th2, characterized by distinct profiles of cytokine production. Th1 cells activate pro-inflammatory effector mechanisms involved in protection and autoimmunity, whereas Th2 cells induce humoral and allergic responses and downregulate local inflammation. Apart from differences in the repertoire of cytokines, no phenotypic attributes are established that distinguish the two subsets. Here we show that Th1 cells, but not Th2 cells, are able to bind to P-selectin and E-selectin. Moreover, only Th1 cells can efficiently enter inflamed sites in Th1-dominated models, such as sensitized skin or arthritic joints, but not in a Th2-dominated allergic response. Immigration of Th1 cells into inflamed skin can be blocked by antibodies against P- and E-selectin. These results provide evidence for adhesion mechanisms to distinguish between the two T helper subsets and mediate their differential trafficking. They indicate that selective recruitment is an additional level of regulation for both effector function profile and character of a local immune response.

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PubMed1997

P-selectin glycoprotein ligand-1 mediates rolling of mouse bone marrow-derived mast cells on P-selectin but not efficiently on E-selectin.

It has been shown recently that mast cells play an essential role as a source of tumor necrosis factor-alpha production during neutrophil recruitment to sites of bacterial infection. Increased numbers of mast cells are indeed noted at sites of wound healing and inflammation. These cells are either recruited from the bone marrow or proliferate locally under cytokine stimulation. Little is known about how mast cell progenitors extravasate into tissue. Using antibody-like fusion proteins of mouse E-selectin and P-selectin, we have analyzed the ability of immature mouse bone marrow-derived mast cells (BMMC) to interact with the endothelial selectins. The P-selectin glycoprotein ligand-1 (PSGL-1) was affinity-isolated from detergent extracts of surface biotinylated BMMC with both selectin-IgG fusion proteins. However, only P-selectin-IgG, but not E-selectin-IgG showed significant interaction with intact BMMC as tested by flow cytometry and cell attachment assays with the immobilized fusion proteins under flow and non-flow conditions at physiological shear stress. Thus, in spite of carrying the necessary carbohydrate modifications which enable solubilized PSGL-1 to bind avidly to E-selectin, PSGL-1 on the surface of BMMC is presented in a way that prevents it from interacting efficiently with E-selectin. Affinity-purified rabbit antibodies against mouse PSGL-1 almost completely blocked the interaction of BMMC with P-selectin-IgG in flow cytometry as well as in cell adhesion assays under static and under flow conditions. Our data reveal that PSGL-1 is the major binding site for P-selectin on mouse BMMC progenitors, but does not support efficient interactions with E-selectin.

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PubMed1997

VE-cadherin antibody accelerates neutrophil recruitment in vivo.

Neutrophils enter sites of inflammation by crossing the endothelial lining of the blood vessel wall. VE-cadherin is an endothelial specific, homophilic adhesion molecule located at the lateral cell surface. We have generated a monoclonal antibody against mouse VE-cadherin which inhibits electrical resistance of endothelial cell monolayers in vitro as well as aggregation of VE-cadherin transfected cells. In vivo, this antibody was found to increase vascular permeability and to accelerate the entry of neutrophils into chemically inflamed mouse peritoneum. Thus, VE-cadherin is essential for the integrity of the endothelial barrier in vivo. Our data suggest that opening of VE-cadherin mediated endothelial cell contacts may be a relevant step during neutrophil extravasation.

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PubMed1997

The E-selectin-ligand ESL-1 is located in the Golgi as well as on microvilli on the cell surface.

Neutrophils and subsets of lymphocytes bind to E-selectin, a cytokine inducible adhesion molecule on endothelial cells. The E-selectin-ligand-1 (ESL-1) is a high affinity glycoprotein ligand which participates in the binding of mouse myeloid cells to E-selectin. The sequence of mouse ESL-1 is highly homologous to the cysteine rich FGF receptor (CFR) in chicken and the rat Golgi protein MG160. We have analysed the subcellular distribution of ESL-1 by indirect immunofluorescence, flow cytometry, various biochemical techniques and by immunogold scanning electron microscopy. We could localize ESL-1 in the Golgi as well as on the cell surface of 32Dc13 cells and neutrophils. Cell surface staining was confirmed by cell surface biotinylation and by cell surface immunoprecipitations in which antibodies only had access to surface proteins on intact cells. In addition, ESL-1(high) and ESL-1(low) expressing cells, sorted by flow cytometry, gave rise to high and low immunoprecipitation signals for ESL-1, respectively. Based on immunogold labeling of intact cells, we localized ESL-1 on microvilli of 32Dc13 cells and of the lymphoma cell line K46. Quantitative evaluation determined 80% of the total labeling for ESL-1 on microvilli of K46 cells while 69% of the labeling for the control antigen B220 was found on the planar cell surface. These data indicate that ESL-1 occurs at sites on the leukocyte cell surface which are destined for the initiation of cell contacts to the endothelium.

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PubMed1996

The E-selectin ligand-1 is selectively activated in Chinese hamster ovary cells by the alpha(1,3)-fucosyltransferases IV and VII.

The E-selectin ligand-1 (ESL-1) has recently been identified as the major ligand on mouse neutrophils using a recombinant antibody-like form of E-selectin as affinity probe. The remarkable selectivity with which ESL-1 can be affinity-isolated is unexplained. Since ESL-1 is endogenously expressed in Chinese hamster ovary (CHO) cells in a non-E-selectin binding form, which can become activated upon transfection of a fucosyltransferase (FucT), we analyzed various CHO cell clones, each overexpressing one of seven different fucosyltransferases, by affinity isolation experiments with E-selectin-IgG. Two of the cell lines were the regulatory CHO mutants LEC11 and LEC12, each overexpressing a different hamster FucT, while the five other clones were stably transfected with human FucTIII to -VII. A large panel of glycoproteins was affinity-isolated with E-selectin-IgG from LEC11 cells and FucTIII transfectants, demonstrating that many different glycoproteins can acquire ligand activity upon alpha(1,3)-fucosylation. In contrast, ESL-1 was almost exclusively isolated as the dominant glycoprotein ligand from LEC12 cells as well as from FucTIV and FucTVII transfectants and less selectively from FucTV and FucTVI transfectants. The selective generation of ligand activity correlated with the selective generation of the HECA452-reactive carbohydrate epitope, which is known to bind to E-selectin. These data suggest that, dependent on the type of fucosyltransferase, ESL-1 is a strongly preferred target molecule for the generation of E-selectin-binding carbohydrate modifications.

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PubMed1996

The role of P-selectin and ICAM-1 in acute lung injury as determined using blocking antibodies and mutant mice.

Cobra venom factor (CVF) induces lung injury through oxidant- and neutrophil-dependent mechanisms. Adhesion molecules, particularly L-selectin, P-selectin, CD11/CD18, and ICAM-1, are required for full expression of injury in rats. This study compared the roles of P-selectin and ICAM-1 using either mutant mice or blocking Abs. Mice deficient in either P-selectin, ICAM-1, or both adhesion molecules were compared with wild-type mice. Wild-type and single mutant mice were given Abs against murine P-selectin or ICAM-1. CVF was injected i.v., and neutrophil sequestration and extravascular albumin were measured 30 min later. Neither P-selectin, ICAM-1, nor P-selectin/ICAM-1 double mutants showed a reduction in neutrophil sequestration or lung injury when compared with wild-type mice. Anti-P-selectin Abs inhibited both sequestration and injury in wild-type mice by 57% and 60%, respectively, but had no effect in P-selectin mutants. Similar results were found using anti-ICAM-1 Ab in wild-type mice (78% inhibition of sequestration and 88% inhibition of injury) and ICAM-1 mutant mice (no reduction). These results suggest that the apparent role of these molecules in CVF-induced lung injury depends on the method used to block function. When studied using blocking Abs, both P-selectin and ICAM-1 were required for neutrophil sequestration and lung injury, while neither played a role singly or together when studied using mice with genetic deletions. Abs may inhibit neutrophil sequestration and lung injury through mechanisms other than simply adhesion blockade, or mutant mice may utilize alternative adhesion pathways.

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PubMed1996

A novel activating anti-beta1 integrin monoclonal antibody binds to the cysteine-rich repeats in the beta1 chain.

The functional status of an integrin depends on the conformation of its extracellular domain, which is controlled by the cell expressing that receptor. The transmission of regulatory signals from within the cell is considered to be via propagated conformational changes from the receptor's cytoplasmic tails to the extracellular ligand binding "pocket." The end result is increased accessibility of the ligand binding pocket in the high affinity ("active") form of integrins. We report a novel monoclonal antibody (QE.2E5) that binds within the cysteine-rich repeats in the integrin beta1 chain and induces high affinity binding of fibronectin to the integrin alpha5beta1. The QE.2E5 epitope is located approximately 200 residues both from the predicted binding site for fibronectin and from the epitopes recognized by other activating anti-beta1 monoclonal antibodies. It is also expressed on beta1 integrins from a number of nonhuman species. Although they have the same functional effects, the binding of QE.2E5 and another activating antibody (8A2) to the receptor have contrasting effects on the expression of an activation-dependent epitope in the beta1 chain. We propose that the cysteine-rich repeats contain a regulatory region that is distinct from those previously described in the integrin beta1 chain.

Amino Acid Sequence↗

PubMed1996

Ligand-specificity of the selectins.

The selectins are carbohydrate-binding cell adhesion molecules acting in the vascular system. They mediate the docking of leukocytes to the blood vessel wall and the rolling of these cells along the endothelial cell surface. These adhesion phenomena initiate the entry of leukocytes into sites of inflammation as well as the migration of recirculating lymphocytes into secondary lymphoid tissues. Blocking selectin function with antibodies or oligosaccharides has proven to be beneficial in various animal models of inflammation and models of ischemia/reperfusion damage. This has raised much interest in the identification of the physiological ligands of the selectins. Several glycoprotein ligands have been identified, some of which can even be selectively isolated from cellular detergent extracts using a selectin as an affinity probe. Four of these "high affinity" ligands have been cloned. The structural requirements of their interaction with the selectins is discussed.

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PubMed1996

Crucial role of 55-kilodalton TNF receptor in TNF-induced adhesion molecule expression and leukocyte organ infiltration.

Stimulation of leukocyte adhesion to the endothelium by TNF is mediated by the up-regulation of adhesion molecules on the endothelial cell surface. C57BL/6 mice and syngenic 55-kDa TNF receptor-deficient mice (TNFRp55-/- mice) were challenged with TNF, and the kinetics of intracellular adhesion molecule-1, ICAM-1, mucosal addressin cell adhesion molecule-1, vascular adhesion molecule-1 (VCAM-1), and E-selectin expression were examined in various organs. TNF induced sustained VCAM-1 expression within 4 h in lung, liver, and kidney. In the lungs, but not in other organs, transient E-selectin expression was induced by TNF within 0.5 h and peaked at 4 h. The TNF-induced expression of VCAM-1 and E-selectin was found to be exclusively controlled by the 55-kDa TNF-receptor (TNFRp55) as demonstrated by analysis of TNFRp55-/- mice. Furthermore, TNF triggered mononuclear cell and neutrophil infiltration of lung, liver, and kidney in C57BL/6 mice but not TNFRp55-/- mice. Interestingly, MAdCAM-1 expression in the marginal sinus of the spleen was detected in wild-type mice but was absent in TNFRp55-/- mice. Together, the data suggest that in vivo the 55-kDa TNF receptor mediates the induction of VCAM-1 and E-selectin expression and is critically involved in the control of leukocyte organ infiltration.

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PubMed1996

Molecular cloning and expression of murine vascular endothelial-cadherin in early stage development of cardiovascular system.

An early step in the formation of the extraembryonic and intraembryonic vasculature is endothelial cell differentiation and organization in blood islands and vascular structures. This involves the expression and function of specific adhesive molecules at cell-to-cell junctions. Previous work showed that endothelial cells express a cell-specific cadherin (vascular endothelial [VE]-cadherin, or 7B4/cadherin-5) that is organized at cell-to-cell contacts in cultured cells and is able to promote intercellular adhesion. In this study, we investigated whether VE-cadherin could be involved in early cardiovascular development in the mouse embryo. We first cloned and sequenced the mouse VE-cadherin cDNA. At the protein level, murine VE-cadherin presented 75% identity (90%, considering conservative amino acid substitutions) with the human homologue. Transfection of murine VE-cadherin cDNA in L cells induced Ca(++)-dependent cell-to-cell aggregation and reduced cell detachment from monolayers. In situ hybridization of adult tissues showed that the murine molecule is specifically expressed by endothelial cells. In mouse embryos, VE-cadherin transcripts were detected at the very earliest stages of vascular development (E7.5) in mesodermal cells of the yolk sac mesenchyme. At E9.5, expression of VE-cadherin was restricted to the peripheral cell layer of blood islands that gives rise to endothelial cells. Hematopoietic cells in the center of blood islands were not labeled. At later embryonic stages, VE-cadherin transcripts were detected in vascular structures of all organs examined, eg, in the ventricle of the heart, the inner cell lining of the atrium and the dorsal aorta, in intersomitic vessels, and in the capillaries of the developing brain. A comparison with flk-1 expression during brain angiogenesis revealed that brain capillaries expressed relatively low amounts of VE-cadherin. In the adult brain, the level of VE-cadherin transcript was further reduced. By immunohistochemistry, murine VE-cadherin protein was detected at cell-to-cell junctions of endothelial cells. Overall, these data demonstrate that VE-cadherin is an early, constitutive, and specific marker of endothelial cells. This distinguishes this molecule from other cadherins and suggests that its expression is associated with the early assembly of vascular structures.

Amino Acid Sequence↗

PubMed1996

Absence of trauma-induced leukocyte rolling in mice deficient in both P-selectin and intercellular adhesion molecule 1.

Leukocyte recruitment during inflammation is achieved through a multistep paradigm that includes margination, selectin-mediated rolling, beta 2 integrin-mediated firm adhesion, emigration, and migration into the site of inflammation. We have used the mouse cremaster muscle as a model of trauma- and cytokine-induced inflammation to study the possible role of intercellular adhesion molecule (ICAM) 1 in leukocyte rolling using gene-targeted mice deficient in ICAM-1, P-selectin, and a combination of P-selectin and ICAM-1. Rolling flux and average leukocyte rolling velocity in ICAM-1-deficient mice was not different from wild-type mice, but P-selectin/ICAM-1-deficient mice showed a total absence of rolling for at least 2 h after surgical trauma. Rolling in both wild-type and ICAM-1-deficient mice 60-120 min after trauma was significantly inhibited by a P-selectin monoclonal antibody (mAb) (RB40.34). In contrast, an mAb (KAT-1) blocking ICAM-1 binding to leukocyte function-associated antigen 1 did not block residual rolling in P-selectin-deficient mice. TNF-alpha induced leukocyte rolling in P-selectin/ICAM-1-deficient mice, but the rolling flux fraction was significantly lower than in TNF-alpha-treated ICAM-1-deficient mice. Leukocyte rolling in P-selectin/ICAM-1-deficient mice treated with TNF-alpha for 3 h was completely blocked by an E-selectin mAb (9A9E3), and partially by an L-selectin mAb (MEL-14). This clearly demonstrates E-selectin-dependent rolling in vivo. Leukocyte rolling velocities were significantly reduced after TNF-alpha treatment and were similar in wild-type and gene-targeted strains. We conclude that the residual trauma-induced leukocyte rolling seen in P-selectin-deficient mice is completely abolished by concomitant ICAM-1 deficiency. This severe defect in leukocyte rolling may explain the absence of leukocyte recruitment into the inflamed peritoneal cavity of P-selectin/ICAM-1-deficient mice at early time points (< or = 4 h).

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PubMed1996

E-selectin expression in experimental models of inflammation in mice.

E-selectin (CD62E, formerly termed ELAM-1) is a cytokine-inducible adhesion molecule which mediates the binding of neutrophils, monocytes, and skin homing T-cells. The murine homologue of E-selectin has been cloned. A monoclonal antibody (21KC10) was used here to study immunohistochemically the expression and regulation of murine E-selectin in vitro and in vivo. As described for the human system, there was no staining of normal endothelium in skin and other tissues. LPS and tumour necrosis factor-alpha (TNF-alpha), but not interleukin-4 (IL-4) or interferon-gamma (IFN-gamma), induced a transient expression of E-selectin, both when injected in vivo and when added to endothelial cell lines in vitro. To analyse temporal expression of E-selectin under pathophysiological conditions in vivo, we chose two murine models of inflammation: allergic (ACD) and irritant contact dermatitis (ICD). Expression of E-selectin was found to be induced on vascular endothelium of post-capillary venules in both ACD and ICD. In ICD, maximal staining of endothelial cells occurred earlier than in ACD. Expression of E-selectin during ICD and ACD was then compared between strains of mice which differ with regard to the intensity of their inflammatory reaction. BALB/c mice, which in contrast to C57BI/6 mice show a denser infiltrate and prolonged influx of granulocyte and monocytes, revealed a more pronounced and more prolonged expression of E-selectin than C57BI/6 mice. This held true for both ACD and ICD, and in each case, peak expression of E-selectin was associated with the highest density of the leukocytic infiltrate. This study thus reveals regulatory mechanisms involved in the expression of murine E-selectin in vivo and in vitro. It also demonstrates a correlation between endothelial expression of E-selectin and the genetically determined intensity of the inflammatory response.

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PubMed1996

Activated T cells induce expression of E-selectin in vitro and in an antigen-dependent manner in vivo.

E-selectin is an endothelial adhesion molecule for polymorphonuclear cells, monocytes and skin-homing T cells. We have analyzed whether murine T cells are able to induce expression of E-selectin in vitro and in vivo. Using models of inflammation in which T cells play either a significant or only a minor role, we compared induction of E-selectin between normal mice and mice lacking functional T cells (athymic nude mice). In irritant contact dermatitis, a model without a major role for T cells, E-selectin was transiently expressed within the first 24 h in both normal and nude mice. In experimental leishmaniasis (where specific T cells play an important role), a high expression of E-selectin was maintained for 48 h in normal mice, whereas in nude mice expression was only transient. However, reconstitution of nude mice with 10(8) T cells from draining lymph nodes (LN) of Leishmania-infected normal mice could restore sustained expression of E-selectin. Transfer of T lymphocytes from normal LN or from LN of mice sensitized to the contact allergen trinitrochlorobenzene (TNCB) did not have this effect. T cells from TNCB-sensitized mice, however, did induce sustained expression of E-selectin in nude mice when TNCB was applied locally; here, reconstitution with Leishmania-specific T cells had no effect. In vitro, T cells from infected or TNCB-sensitized normal mice increased expression of E-selectin on microvascular endothelial cells after 4 h of co-culture. T cells from untreated mice were less effective. Induction was dependent on direct cell-cell contact, but not on the action of interleukin-1 alpha, interleukin-1 beta, tumor necrosis factor-alpha or interferon-gamma. We conclude that sensitized T cells induce sustained expression of E-selectin in vivo in an antigen-dependent manner. This novel way of regulation could be relevant for cell-mediated immunity and chronic disease. The mechanisms are unknown, but, as in vitro, might require direct cell-cell contact.

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