Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Phagocytes express a family of structurally related receptors, LFA-1, CR3, and p150,95, that mediate adhesion of leukocytes to a variety of cells and surfaces. LFA-1 mediates the binding of killer T cells to targets, CR3 mediates binding of phagocytes to iC3b-coated surfaces and to endothelial cells, and LFA-1, CR3, and p150,95 each mediate the binding of bacterial lipopolysaccharide. Here we review the structure and function of each of these receptors and present evidence that they are related to a larger class of adhesion-promoting receptors called integrins. Of particular emphasis are observations that the capacity of these receptors to promote adhesion is strongly and reversibly modulated by both soluble and surface-bound stimuli. We review this form of regulation and present evidence that changes in the binding activity of adhesion-promoting receptors is accomplished by changes in the two-dimensional distribution of receptors in the plane of the membrane. Inactive receptors are randomly distributed in the membrane, and their ability to bind a ligand-coated surface is enabled by a ligand-independent movement into small clusters. The implications of these structural features are discussed.
 ...
PMID:Adhesion-promoting receptors on phagocytes. 297 19

Monocytes in a familial monocyte disorder, a recently recognized primary immunodeficiency syndrome, with impaired phagocytic functions were studied for their ability to produce interleukin 1 (IL-1) as well as the surface property. Monocytes from two children (siblings) with the disorder possessed CD11b, CD13, CD14, CD33, Ia and LFA-1/Mac-1/p150,95 beta subunit antigens as determined by flow cytometry. Electron microscopic cytochemistry showed that the monocytes had surface glycoproteins reactive with four representative lectins. The IL-1 production by monocytes was assayed in the two patients and compared with that in six children with primary immunodeficiency syndromes and some monocyte abnormalities; three had congenital neutropenia, two had hyper-IgE syndrome, and one had defective monocyte chemotaxis. Monocyte culture supernatants were prepared with stimulation by lipopolysaccharide or silica, and their IL-1 activity was measured by the mouse thymocyte-proliferation assay. The patients' monocytes were defective in IL-1 production: the values were less than 1.0% of the control monocyte values (n = 12) and were in contrast with those of congenital neutropenia monocytes of 186.2% to 204.3%. These results demonstrate a familial monocyte disorder which is characteristic among the immunodeficiency syndromes with regard to the defective IL-1 production and the impaired phagocytic functions.
 ...
PMID:Defective interleukin-1 production in a familial monocyte disorder with a combined abnormality of mobility and phagocytosis-killing. 326 74

We examined the role of the neutrophil membrane antigen complex designated CDw18 (LFA-1/Mac-1/p150, 95) in human peripheral blood neutrophil adherence to cultured human umbilical vein endothelial cells (HEC) pretreated with lipopolysaccharide (LPS), interleukin 1 (IL 1), or recombinant tumor necrosis factor-alpha (rTNF-alpha). Pretreatment of HEC with LPS produced a dose-and time-dependent increase in subsequent neutrophil adherence (7 +/- 1% adherence to untreated HEC vs 38 +/- 3% adherence to HEC pretreated for 4 hr with LPS 150 ng/ml; mean +/- SE of 22 experiments: p less than 0.001). This effect was observed in primary and passaged HEC, but not in bovine aortic endothelial cells or human dermal fibroblasts. The LPS-induced activity appeared to be associated with the HEC surface, since it was not removed by washing and was not detected in the supernatant medium. Inhibition of RNA or protein synthesis during pretreatment of HEC with LPS prevented induction of the adherence-promoting activity. Pretreatment of HEC with IL 1 and rTNF-alpha produced a similar protein synthesis-dependent increase in neutrophil adherence to HEC. Coincubation of neutrophils with murine monoclonal antibody (MoAb) 60.3, an antibody directed to the CDw18 complex, produced a 70 +/- 4% inhibition of neutrophil adherence to LPS-pretreated HEC, 59 +/- 5% inhibition of adherence to IL 1-pretreated HEC, and 65 +/- 11% inhibition of adherence to rTNF-alpha-pretreated HEC (means +/- SE of 18, seven, and five experiments, respectively). Notably, MoAb 60.3 did not completely inhibit neutrophil adherence to pretreated HEC, although it completely inhibited adherence to untreated HEC when neutrophils were activated directly with phorbol ester. Similarly, the adherence of neutrophils from a patient with an inherited deficiency of the CDw18 complex to LPS-, IL 1-, and rTNF-alpha-pretreated HEC was markedly reduced compared with normal neutrophils (5 to 11% adherence with CDw18-deficient neutrophils vs 43 to 54% adherence with normal neutrophils), but adherence to pretreated HEC was still significantly greater than adherence to HEC that were not pretreated (2% adherence). We conclude that LPS, IL 1, and rTNF-alpha induce synthesis of an endothelial cell-surface factor(s) that promotes neutrophil adherence primarily by a mechanism involving the CDw18 complex. It thus appears that the CDw18 complex is important for augmented neutrophil adherence to endothelium in vitro whether the is stimulated directly by inflammatory mediators or indirectly by endothelial-dependent mechanisms.
 ...
PMID:An endothelial cell surface factor(s) induced in vitro by lipopolysaccharide, interleukin 1, and tumor necrosis factor-alpha increases neutrophil adherence by a CDw18-dependent mechanism. 348 3

When lymphocytes are activated in vitro, discrete cell-cell contacts are initiated which result in cluster formation. This contact interaction is found in syngeneic or allogeneic mixed leukocyte reactions as well as in mitogen-stimulated cultures (concanavalin A, periodate, lipopolysaccharide). T cells as well as B cells display the binding phenomenon. This activation-dependent lymphocyte-lymphocyte adhesion involves LFA-1, since monoclonal antibodies (including Fab fragments) against this molecule inhibit adhesion between clustering lymphocytes in a dose-dependent manner, whereas antibodies directed to several other cell surface antigens are inactive. Since a wide variety of functional interactions are inhibited by antibodies to LFA-1, it may be concluded that LFA-1-mediated cell contact is a discrete and essential step between a recognition event and the generation of functional activities by lymphocytes in general.
 ...
PMID:Contact interaction between lymphocytes is a general event following activation and is mediated by LFA-1. 352 48

We report here that human macrophages bind Escherichia coli by recognizing bacterial lipopolysaccharide (LPS). Purified LPS was inserted into erythrocyte membranes, and the resulting LPS-coated red cells were bound by macrophages with the same temperature and cation dependence as observed for E. coli. When receptors for LPS were withdrawn from the plasma membrane by spreading the macrophages on LPS-coated surfaces, the binding of E. coli was blocked. We have also identified the receptors on macrophages that recognize LPS. Macrophages express three structurally homologous cell surface proteins, CR3, lymphocyte function-associated antigen (LFA-1), and p150,95. We used surface-bound monoclonal antireceptor antibodies to selectively remove these proteins from the apical surface of macrophages. We found that each of these proteins mediated the binding of E. coli to macrophages.
 ...
PMID:Adhesion-promoting receptors on human macrophages recognize Escherichia coli by binding to lipopolysaccharide. 353 92

The kinetics of the binding of an anti-LFA-1 monoclonal antibody to lymphocytes of the B and T lineages was studied. A Kd approximately ten times lower was observed when binding the antibody to B splenocytes compared to T splenocytes. Using Fab fragments and measuring the dissociation rate constants gave a similar difference in binding kinetics of anti-LFA-1 between the different splenocytes. This difference of cell-binding affinity was independent of the state of stimulation of the cells by lipopolysaccharide or concanavalin A. Thymocytes reacted with the antibody with the same Kd as T splenocytes. The combined results indicate that LFA-1 from B and from T lymphocytes have a different conformation. Binding with a higher affinity to B and a lower affinity to T lymphocytes could also be demonstrated using liposomes coated with anti-LFA-1 antibody.
 ...
PMID:Lymphocyte function-associated antigens one (LFA-1) on B and on T lymphocytes bind a monoclonal antibody with different affinities. 388 42

Previous findings provided evidence that bacterial lipopolysaccharide (LPS)-activated human monocytes are able to upregulate autologous polymorphonuclear (PMN) phagocytic ability via cell-to-cell contact mechanisms mediated by membrane (m)-associated cytokines (CKs), such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-1 alpha, IL-1 beta, IL-6 and IL-8. Consequently, the role of the lymphocyte function-associated antigen (LFA)-1 molecule on the monocyte (Mo)-PMN interplay was evaluated. In the first step, lipid A (LA)-stimulated Mo were pretreated with anti-recombinant human (Rhu) LFA-1 alpha monoclonal antibody (MoAb), and the enhanced phagocytic activity of PMN was abrogated. Pretreatment of unstimulated Mo with the same MoAb led to a reduction of PMN phagocytosis. In the second step, the role of m-LFA-1 on PMN was investigated with regard to Mo modulation. Anti-Rhu LFA-1 alpha MoAb was supplemented to LA-activated and unstimulated PMN, respectively, before coculturing with autologous LA-activated Mo. The addition of anti-Rhu LFA-1 alpha MoAb gave rise to a significant decrease in PMN phagocytosis regardless of PMN activation. These data suggest that, besides m-CKs, LFA-1 present on Mo and PMN might be involved in the mutual interplay between PMN and Mo.
 ...
PMID:Role of lymphocyte function-associated antigen-1 on the interplay between lipid A-activated monocytes and polymorphonuclear cells. 747 67

We have characterized a defect in the pulmonary recruitment of neutrophils (PMNs) in rats with experimental endotoxemia. Rats pretreated with intravenous (IV) 0.9% saline (NaCl) showed abundant PMNs in bronchoalveolar lavage (BAL) fluid after intratracheal (IT) lipopolysaccharide (LPS) (5 mg/kg) (54.27 +/- 9.80 x 10(6), n = 7, versus IT saline, 0.73 +/- 0.62 x 10(6), n = 4). In contrast, endotoxemic rats (IV LPS 1.0 mg/kg) failed to show PMN influx after IT LPS (0.40 +/- 0.13 x 10(6) PMNs in BAL fluid, n = 7). Four hours after the IT administration of LPS, the chemotactic activity of BAL fluid from endotoxemic rats (87 +/- 9.92% of maximal chemotaxis toward zymosan-activated serum [ZAS], n = 4) was not significantly different (P > 0.05), from rats pretreated with IV NaCl (61.09 +/- 6.17% of maximal chemotaxis toward ZAS, n = 4). Endotoxemic and control rats showed similar chemotactic gradients in determinations of the BAL/plasma chemotactic activity ratio (BAL/plasma ratio: 2.16 +/- 0.14, n = 4, IV NaCl versus 2.98 +/- 0.14, n = 4, IV LPS, P > 0.05). Serum from untreated rats, rats pretreated with IV NaCl, and endotoxemic rats caused minimal effects on rat PMN chemotaxis in vitro (78.17 +/- 8.16%, 79.29 +/- 7.09%, and 69.28 +/- 9.04% of maximal chemotaxis toward ZAS, respectively, n = 4/group, P > 0.05). Quantitation of PMN adhesion molecules revealed a loss of L-selectin (8 +/- 5% of control group, n = 3), an increase in Mac-1 (776 +/- 82.60% of control group, n = 3), and no change in LFA-1 when normal PMNs were incubated with plasma from rats pretreated with IV LPS (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Defective pulmonary recruitment of neutrophils in a rat model of endotoxemia. 752 72

Normal ICR mice developed severe liver injury when they were given intravenous injections of Propionibacterium acnes and lipopolysaccharide (LPS) with a 7 day interval. In contrast, T cell-deficient ICR nude mice were resistant to P. acnes and LPS-induced liver injury. However, athymic ICR nude mice, which were treated with cell transfer of normal ICR mouse spleen cells (10(8) cells) or ICR mouse nylon-wool passed splenic T-enriched cells (over 10(7) cells), showed severe liver injury as assessed by elevation of serum transaminase activities. Histological analyses also demonstrated that the transferred cells migrated into the liver of nude mice to induce liver injury. However, depletion of both CD4+ T cells and CD8+ T cells from transferred cell populations caused a marked decrease in the elevation of serum transaminase, indicating the actual involvement of T cells in liver injury. Moreover, in vivo administration of anti-LFA-1 mAb blocked P. acnes and LPS-induced liver injury in nude mice following T cell transfer. Thus, this model will provide a new strategy to investigate T cell-dependent cell-cell interaction during the induction of liver damage.
 ...
PMID:Establishment of a T cell-dependent nude mouse liver injury model induced by Propionibacterium acnes and LPS. 776 41

Nickel, cobalt and chromium are metals very often implicated in allergic contact dermatitis. In vivo, keratinocytes, which are the first target cells, can be directly activated to participate in the local reaction, especially through the expression of the membrane antigen ICAM-1, a ligand of the leucocyte antigen LFA-1, and the production of cytokines. Our aim was to assess the effects of sensitizing metal haptens (nickel, cobalt and chromium) compared with the toxic metal cadmium on the induction of ICAM-1 and the production of TNF alpha by epidermal cells. For this purpose, normal human keratinocytes obtained during plastic skin surgery were cultured in low-calcium defined medium (MCDB153) and the metals were used in non-toxic concentrations. Using FACS analysis, ICAM-1 expression was found to be induced only by nickel. This stimulation appeared as early as 24 h after stimulation. All the metals induced a low expression of TNF alpha detectable by immunocytochemistry correlating with the induction of the nuclear stress protein Hsp72 which is closely linked genetically with the TNF alpha locus. However, only Ni2+, Co2+ and Cr2+ induced a significant release of TNF alpha detectable by ELISA after 48 h stimulation. This secretion was lower than that observed with known stimulants such as lipopolysaccharide. These results indicate that the metals studied are able to induce an aggressive cellular effect, and that nickel, by its ICAM-1 induction, may play a major role in the keratinocyte activation state during allergic contact dermatitis.
 ...
PMID:Effect of various metals on intercellular adhesion molecule-1 expression and tumour necrosis factor alpha production by normal human keratinocytes. 786 60


<< Previous 1 2 3 4 5 6 Next >>