UNIPROT:P43026 - FACTA Search

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Query: UNIPROT:P43026 (lipopolysaccharide)
62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A monoclonal immunoglobulin G1 (IgG1) antibody (mAb), designated mNI-11, was produced by immunizing mice with the lipopolysaccharide (LPS)-stimulated monocyte-like cell line U937. The reactivity of mNI-11 was tested by the indirect immunofluorescence method. The antigen defined by mNI-11 was found to be expressed on U937 cells, LPS-stimulated U937 cells, normal CD14+ cells (monocytes/macrophages), and human umbilical vein endothelial cells (HUVECs). Expression of the antigen defined by mNI-11 on HUVECs slightly increased in response to exposure to tumor necrosis factor-alpha (TNF-alpha) and phorbol myristate acetate (PMA). When the reactivity of mNI-11 and mAbs binding human differentiation antigens such as CD11a, CD11b, CD11c, CD14, CD16, CD18, CD23, CD28, CD29, CD31, CD43, CD44, CD45RA, CD49d, CD50, CD54, CD58, CD80, CD102, CD106, HLA-class I, or HLA-class II antigen was compared, no mNI-11 reactivity resembling that of these mAbs was found. mNI-11 markedly induced homotypic cell aggregation of U937 cells when they were stimulated with LPS. The mNI-11-induced aggregation of LPS-stimulated U937 cells, referred to as LPS-U937 cells, required neither Fc receptor engagement nor cross-linking of the antigen defined by mNI-11 because aggregation was induced by both F(ab')2 fragments and monovalent F(ab') fragments of mNI-11. The mNI-11-induced aggregation was blocked by the addition of ethylenediaminetetraacetate, and also when incubated at 4 degrees C. mAbs to CD11a/CD18 (lymphocyte-function associated antigen-1; LFA-1) and CD54 (intercellular adhesion molecule-1; ICAM-1) completely blocked the LPS-U937 cell aggregation induced by mNI-11. The LPS-U937 cell aggregation induced by mNI-11 was partially but not completely blocked by the protein kinase C inhibitors sphingosine and H-7, and was completely blocked by the protein-tyrosine kinase inhibitor genistein. Interestingly, mNI-11 markedly promoted LPS-U937 cell adhesion to HUVECs. The mNI-11-induced LPS-U937 cell adhesion to HUVECs was not reduced in the presence of LFA-1 (CD11a/CD18) or ICAM-1 (CD54) mAbs. On the other hand, LPS-U937 cells, whether treated with mNI-11 or not, sufficiently adhered to the extracellular matrix protein fibronectin, but not to laminin or collagen type I. However, mNI-11 did not markedly promote LPS-U937 cell adhesion to fibronectin. Adhesion of LPS-U937 cells treated with mNI-11 to fibronectin was completely blocked by CD29 (beta chain of very late antigens) mAb. The surface antigen recognized by mNI-11 had a molecular size of approximately 97 kDa under non-reducing conditions and approximately 117 kDa under reducing conditions, as determined by immunoblotting analysis. We found that mNI-11 recognizes an adhesion-associated molecule distinct from any previously reported in terms of its pattern of cellular distribution and molecular weight, and also found that mNI-11 has activity which induces cell adhesion/aggregation of U937 cells when stimulated with LPS.
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PMID:Development and characterization of a novel monoclonal antibody (mNI-11) that induces cell adhesion of the LPS-stimulated human monocyte-like cell line U937. 865 55

Hemodialysis with complement-activating membranes such as cuprophane is known to transiently activate leukocytes, leading to increased cellular adhesiveness, pulmonary leukostasis, and reduced functional capacity of monocytes and neutrophils. Clinically, this repetitive cell activation may contribute to the increased morbidity and mortality associated with chronic hemodialysis. To examine the effect of cuprophane hemodialysis on expression of cell-surface proteins involved in leukocyte adhesiveness, we monitored CD11b, CD18, CD14, CD54, and plasma-soluble CD54 in 10 patients during hemodialysis with cuprophan dialyzers. To test the effect of local blood recirculation, in two patients, arterial supply to the dialyzer was accessed from the peripheral arteriovenous fistula and was returned via an indwelling central venous catheter. In an attempt to examine the possible role of membrane-induced complement activation, the results were compared with those seen after incubation with C5a in vitro. Finally, the leukocyte responses to C5a and lipopolysaccharide were measured before and after hemodialysis. Leukocyte expression of CD11b and CD18 increased and CD14 decreased with hemodialysis, while CD54 remained unaltered. Plasma CD54 was markedly elevated before and remained unchanged during hemodialysis. Data obtained with C5a activation in vitro revealed identical changes in CD11b expression as that seen with hemodialysis, suggesting the role of membrane-induced complement activation. Preliminary data obtained using remote arterial and venous access sites showed only a slight increase in CD11b expression in the arterial blood, suggesting that the apparent systemic activation seen with arteriovenous access may be due to recirculation and local activation within the blood access. Finally, dialysis procedure did not impair lipopolysaccharide- or C5a-mediated upregulation of CD11b expression.
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PMID:Effect of hemodialysis on leukocyte adhesion receptor expression. 865 1

To determine actions of acute intoxication on pathophysiologic responses to trauma, anesthetized and ventilated mongrel pigs received a 20% solution of ethanol (EtOH) by an intravenous (IV group; 2 g/kg, n = 8) or an oral (PO group; 3 g/kg, n = 12 x 60 minutes) route of administration, or the lactated Ringer's vehicle (LR group; n = 12). After 60 minutes, all were subjected to soft tissue injury and 30 to 35% hemorrhage, 60-minute shock, and then resuscitation, with shed blood plus supplemental LR. After 3 days, host defense was challenged with Escherichia coli lipopolysaccharide (LPS); (1 microgram/kg x 30-minutes IV). The supplemental resuscitation was identical (50-53 mL/kg/hours), but posttraumatic acidosis was observed in the IV group and the PO group (base deficit = 4.4 +/- 1.3 and 5.5 +/- 0.9 mEq/L) and not in the LR group. After 3 days, the acid-base equilibrium was restored, but a difference in host defense was unmasked by LPS. In the LR group, LPS-evoked pulmonary vasoconstriction was followed by decreased compliance and ventilation-perfusion mismatch, which was associated at 3 to 5 hours with a base deficit, reduced SVO2, and reduced PO2 (-0.5 +/- 0.2 mEq/L, 46 +/- 1%, 127 +/- 1 mm Hg). These changes were blunted in the PO group (2.0 +/- 0.1 mEq/L, 56 +/- 1%, 183 +/- 4 mm Hg) and potentiated in the IV group (-4.3 +/- 0.5 mEq/L, 40 +/- 2%, 60 +/- 2 mm Hg), even though more fluid was required to maintain systemic arterial and cardiac filling pressures following LPS administration in the IV (40 +/- 6 mL/kg/ hours) versus the LR or PO groups (31 +/- 5 or 23 +/- 3). The PO versus LR differences could not be attributed to enteral nutrition because an isocaloric solution of 50% dextrose had no effect versus LR solution. EtOH caused neutropenia following trauma, relative to LR solution, but the IV versus PO differences could not be discriminated on the basis of neutrophil or lymphocytes counts, nor CD18 receptor expression, nor renal or hepatic dysfunction. However, T4 lymphocytes and cortisol, a nonspecific index of inflammation, were higher for at least 24 hours after trauma with IV, relative to PO or LR. Blood EtOH was similar with IV or PO during resuscitation (100-120 mg/dL), but the kinetics were different prior to trauma. With PO, blood EtOH slowly accumulated to a steady state plateau, the level of which was higher with no anesthesia or no trauma. With IV, blood EtOH peaked at 275 mg/dL and then exponentially declined with a rate that was not influenced to a major extent by trauma or by anesthesia. Therefore: 1) EtOH absorption is impaired during trauma (in part because of reduced gut blood flow); 2) acute EtOH intoxication at the time of trauma altered neutrophils, plasma cortisol, and T4 lymphocytes during recovery and host defense to a superimposed LPS challenge. The apparently favorable effect of PO versus IV EtOH on the response to endotoxemia after trauma probably reflects differences in the kinetics of blood EtOH in the interval before reperfusion but a "first pass" effect (metabolism in the gut or liver) might also explain the data.
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PMID:Acute ethanol intoxication and endotoxemia after trauma. 867 25

This study investigated the role of intracellular calcium concentration ([Ca]i) as a possible intermediate in the lipopolysaccharide (LPS) second messenger pathway for the activation of neutrophils (polymorphonuclear leukocytes [PMNs]). Isolated PMNs were loaded with the calcium-sensitive fluorescent dye fura-2. The PMNs were stimulated with either LPS or the positive control formyl-Met-Leu-Phe (fMLP). As expected, PMN exposure to fMLP increased [Ca]i. However, LPS stimulation did not induce any detectable changes. Depletion of intracellular Ca stores with thapsigargin, or extracellular Ca with EGTA, significantly inhibited the upregulation of the CD11b/CD18 integrin in response to fMLP but not LPS. We conclude that [Ca]i is not an early intermediate in the second-messenger pathway for the activation of PMNs by LPS.
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PMID:Role of calcium during lipopolysaccharide stimulation of neutrophils. 869 14

OM-85 BV is a preparation of bacterial extracts which proved to be of some efficacy in the prevention of respiratory tract infections. However, the mechanisms of action of this drug remain unclear. As we recently observed that OM-85 BV upregulates the expression of adhesion molecules on phagocytes, we took advantage of this property to determine whether the activating effects of OM-85 BV on monocytes and granulocytes depend on its interaction with CD14 molecules. Indeed, CD14 represents the major cell surface receptor for lipopolysaccharide and other bacterial products at the surface of leucocytes. First, we found that the upregulation of Mac-1 (CD11b/CD18) induced in vitro by OM-85 BV on monocytes was not blocked by an anti-CD14 monoclonal antibody (mAb) which inhibits monocyte responses to lipopolysaccharide. Similarly, the anti-CD14 mAb inhibited upregulation of Mac-1 on granulocytes when it was induced by lipopolysaccharide but not by OM-85 BV. To confirm that the effects of OM-85 on the expression of Mac-1 is CD14-independent, we analysed the responses of a patient with paroxysmal nocturnal haemoglobinuria, a disease associated with a defect of CD14 expression at the membrane of phagocytes. We found that monocytes and granulocytes of this patient displayed an impairment in Mac-1 upregulation in response to lipopolysaccharide whereas they responded normally to OM-85 BV. We conclude that OM-85 BV activates phagocytes through a CD14-independent pathway. The characterisation of the cell surface receptors of monocytes and granulocytes involved in the interactions with OM-85 BV might provide a molecular clue to the mode of action of this preparation of bacterial extracts.
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PMID:OM-85 BV upregulates the expression of adhesion molecules on phagocytes through a CD 14-independent pathway. 889 5

A monoclonal antibody (mAb), designated mNI-58A, was produced by immunizing mice with the lipopolysaccharide (LPS)-stimulated monocyte-like cell line, U937. The antigen defined by mNI-58A was widely expressed on various lymphoid cells and all cell lines examined except the erythroid cell line, K562. When the reactive patterns between mNI-58A and the mAbs to various human differentiation antigens (CD11a, CD11b, CD11c, CD14, CD16, CD18, CD23, CD28, CD29, CD31, CD43, CD44, CD45RA, CD50, CD54, CD58, CD80, CD102, CD106, HLA-class I and-class II antigen) were compared, that of mNI-58A was found to be similar to those of the leukocyte function-associated antigen-1 (LFA-1) mAbs. Using a competitive immunofluorescence binding assay it was found that the preincubation with one of the CD11a mAbs, 2F12 completely blocked the subsequent binding of mNI-58A. mNI-58A prevented the homotypic cell aggregation of the phorbol myristate acetate (PMA)-activated U937 cells (referred to as PMA-U937) and PMA-activated Epstein-Barr virus (EBV)-transformed B cell lines, B-85 and Mann. mNI-58A markedly induced the spread formation of the PMA-U937 cells following this blocking of the homotypic cell aggregation, whereas 2F12 did not under the same condition. The spread formation induced by mNI-58A was completely blocked by cytochalasin B (CyB), cytochalasin D (CyD), cycloheximide (CHX) or protein kinase C inhibitors, sphingosine and H-7. The U937 cells markedly adhered to the tumor necrosis factor-alpha (TNF-alpha)-stimulated human umbilical vein endothelial cells (HUVECs) and also to the extracellular matrix protein, fibronectin, but mNI-58A did not enhance or block these adhesion process. mNI-58A precipitated two glycoproteins with molecular weight 180 kDa and 95 kDa as determined by SDS-PAGE analysis, which were identical to the LFA-alpha (CD11a) and beta (CD18) chains of leukocyte integrin precipitated by the CD11a mAbs, respectively. Sequential immunoprecipitation studies using the CD11a mAb (2F12) also indicate that mNI-58A recognizes an epitope on the alpha-chain of the LFA-1 molecule. The ability of mNI-58A to block the PMA-U937 cells and to induce the spread formation of these cells suggests that mNI-58A is a novel mAb reacting with an epitope on the alpha-chain of LFA-1 different from those recognized with the existing CD11a mAbs.
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PMID:A novel monoclonal antibody mNI-58A against the alpha-chain of leukocyte function-associated antigen-1 (LFA-1) blocks the homotypic cell aggregation and actively regulates morphological changes in the phorbol myristate acetate (PMA)-activated human monocyte-like cell line, U937. 889 74

Bacterial peritonitis is the most important complication of peritoneal dialysis (PD), limiting its widespread application. Conventional glucose-based peritoneal dialysates (G-PDS) depress oxygen consumption, chemiluminescence, superoxide production, phagocytosis, bacterial killing and actin polymerization in neutrophils (PMN) in vitro. Expression of adhesion receptors is critical to leukocyte activation, adhesion, migration and phagocytosis. The effects of G-PDS on basal and stimulated leukocyte adhesion molecule expression and leukocyte adhering capacity is unknown. We examined the effect of a five minutes incubation of whole blood in either HEPES-buffered saline or G-PDS containing 1.5% (83 mM), 2.5% (139 mM) or 4.25% (236 mM) glucose, at pH = 5.2, and pH = 7.4. PMN intracellular pH was measured spectrofluorometrically. Leukocyte CD11b, CD18 and CD14 were measured by flow cytometry using monoclonal antibodies in otherwise unstimulated cells or 60 minutes after lipopolysaccharide (LPS) stimulation. In addition, leukocyte adhering capacity to nylon wool was tested. In an attempt to dissect the effect of high glucose concentrations from that of the attendant hyperosmolality, the experiments were repeated with dialysates in which glucose was substituted by sodium chloride (NaCl-PDS) to attain identical osmolalities. G-PDS, as well as the mixtures of spent and fresh G-PDS, significantly depressed the basal PMN expression of adhesion receptors CD11b and CD18 and monocyte expression of CD14, and substantially mitigated the LPS-mediated up-regulation of CD11b and CD18. Likewise, G-PDS significantly inhibited leukocyte adhering capacity without affecting cell viability. Similar results were observed with NaCl-PDS. The observed abnormalities were primarily osmolality-dependent, and largely intra- and extracellular pH-independent. Impaired adhesion receptor expression and cell adhesion capacity shown here reveal another dimension of the G-PDS-induced leukocyte abnormalities.
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PMID:Effects of conventional peritoneal dialysates on leukocyte adhesion and CD11b, CD18 and CD14 expression. 891 36

The functions of different populations of peripheral blood monocytes in the course of an inflammatory reaction are presently not fully understood. In particular, the mechanisms for their specific recruitment to an inflammatory site are not yet known. We investigated a dexamethasone (Dex)-inducible monocyte subtype and its adhesion to either unstimulated or lipopolysaccharide (LPS)- or interferon (IFN)-gamma-stimulated human umbilical vein endothelial cells (HUVEC). The Dex-induced monocytes were characterized by the expression of the surface glycoprotein RM3/1. It was found that pretreatment of monocytes with Dex increased their adhesion to unstimulated and stimulated HUVEC. This increase in adhesion was paralleled by the expression of the RM3/1 surface molecule. Treatment with cyclosporin A (CsA) caused a down-regulation of the RM3/1 density per cell by 67% and also decreased adhesion to HUVEC. In contrast, the expression of other adhesion molecules remained unaffected by Dex or CsA treatment. Treatment of Dex-induced monocytes with antibodies against RM3/1, CD11a, CD11b, CD11c, CD14 and CD18 resulted in suppression of adhesion to stimulated HUVEC by 46%, 18%, 17%, 12%, 25% and 15%, respectively. Antibodies to the known adhesion molecules on endothelial cells (vascular cell adhesion molecule-1, E-selectin) did not block adhesion of Dex-induced monocytes. However, the combination of antibodies to RM3/1 and CD14 inhibited adhesion to LPS-stimulated HUVEC by 74%. These effects were also seen on IFN-gamma-stimulated HUVEC, where adhesion of Dex-induced monocytes was blocked with antibodies to RM3/1 + CD14 by 63%. From this, it is concluded that the RM3/1-molecule is a novel surface molecule that contributes to the adhesion of cortisone-induced monocytes to LPS or cytokine-stimulated endothelial cells.
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PMID:Identification of a novel surface molecule, RM3/1, that contributes to the adhesion of glucocorticoid-induced human monocytes to endothelial cells. 892 66

The acyl poly(1,3)galactoside (APG) from Klebsiella pneumoniae is a bis-acylated lipopolysaccharide (LPS) devoid of ester-linked fatty acids. APG interacts with CD14 and CD11b/CD18 on monocytes. This study addressed the role of serum proteins in the binding and functional properties of APG as a candidate LPS antagonist. In the absence of serum, APG did not induce tumor necrosis factor alpha (TNF-alpha) synthesis by human mononuclear cells and dose-dependently inhibited their activation induced by different LPS. Conversely, in the presence of 5% autologous plasma, APG activated cells and did not antagonize LPS. Serum decreased APG but not LPS binding to monocytes. Binding competition experiments indicated that APG and LPS competed for the same receptors in serum-free conditions but bound to different receptors in the presence of plasma. The data indicate that serum-dependent LPS receptors do contribute to LPS activation of monocytes but do not recognize deacylated LPS analogues.
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PMID:Alteration of dealcylated lipopolysaccharide antagonistic properties by interaction with plasma factors. 900 May 32

A reconstituted high density lipoprotein (rHDL) containing human apolipoprotein A-I and phosphatidylcholine was tested for its ability to modify polymorphonuclear leukocyte (PMN) adherence to endothelial cells (EC) in vitro. EC stimulation for 4 h with lipopolysaccharide (LPS) or tumor necrosis factor-alpha (TNF alpha) resulted in a four- to sixfold increase in PMN adherence. Concomitant stimulation of EC with LPS and rHDL virtually prevented the LPS-stimulated increase in PMN adherence. Changes in adherence were paralleled by alterations in adhesion molecule expression of EC. Concomitant EC stimulation with LPS and rHDL resulted in complete inhibition of the LPS-stimulated increase in expression of E-selectin and intercellular adhesion molecule 1 (ICAM-1). In contrast, rHDL reduced the TNF alpha-induced expression of adhesion molecules as well as the PMN adherence to TNF alpha-stimulated EC by approximately 10%. The CD11/CD18-mediated PMN adherence to EC as a consequence of PMN stimulation with calcium ionophore (A23187) was diminished in the presence of rHDL after 7 min incubation by 36.1 +/- 11.4% and after 15 min incubation by 45.1 +/- 7.4%. In addition, the A23187-stimulated increase in PMN adherence to fibrinogen-coated surfaces, mediated by CD11b/CD18, was virtually eliminated in the presence of rHDL and HDL, but not in the presence of apolipoprotein A-I or natural low density lipoprotein. FACS analysis showed that PMN treated with rHDL and subsequently washed were resistant to FMLP-induced CD11b/ CD18 up-regulation. In conclusion, these data indicate that rHDL decreases cell adhesion via two mechanisms: blocking LPS activity and modifying CD11b/CD18 up-regulation on PMN.
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PMID:Reconstituted high density lipoprotein modulates adherence of polymorphonuclear leukocytes to human endothelial cells. 906 82

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