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

The effect of conditioned media from Kupffer cells of normal, D-galactosamine- and thioacetamide-treated rats on the synthesis of proteoglycans by rat liver fat-storing cells in culture was studied in order to elucidate some of the mechanisms initiating enhanced connective tissue proteoglycan synthesis in injured liver. The incorporation of [35S]sulfate and [3H]glucosamine into proteoglycans was 2.1-2.5 fold (P less than 0.005) stimulated by the additions of normal, D-galactosamine- and thioacetamide-exposed Kupffer cell media. The concentrations of hexuronic acid and amino sugars in the medium glycosaminoglycan fraction were enhanced 5-fold and 4.5-fold, respectively, if the fat-storing cells were cultured in the presence of normal Kupffer cell conditioned medium. Treatment of normal Kupffer cells in culture with zymosan and phorbol esters, but not the addition of lipopolysaccharide, enhanced further the proteoglycan synthesis-stimulating effect of normal (untreated) Kupffer cells. The pattern of newly formed [35S]sulfate-labeled proteoglycans was changed in the presence of Kupffer cell media, showing a strong fractional increase of chondroitin sulfate and a relative decrease of dermatan sulfate, but the fraction of heparan sulfate was almost unaffected. In absolute terms Kupffer cells stimulated the total (medium and cell fraction) synthesis of chondroitin sulfate 2.8-fold and that of dermatan sulfate 1.5-fold. Although the DNA content of fat-storing cell cultures was increased by incubation with Kupffer cell media, an enhancement of proteoglycan synthesis was also observed when related to the DNA content of the cultures. The stimulation of proteoglycan synthesis was not dependent on the induction of cell proliferation. Gel chromatography and beta-elimination of medium proteoglycans revealed no changes of the molecular weight distribution profile of native proteoglycans and glycosaminoglycan chains synthesized under the influence of the various Kupffer cell media. Activation of proteoglycan synthesis and secretion in fat-storing cells by Kupffer cell-derived factor(s) might be an important mechanism of their strong accumulation in the connective tissue of fibrotic livers.
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PMID:Kupffer cell-mediated induction of synthesis and secretion of proteoglycans by rat liver fat-storing cells in culture. 342 38

Monocytes from moderately eosinophilic individuals secrete material that enhances the cytotoxic activity of eosinophils against antibody-coated schistosomula of Schistosoma mansoni. This material is not a single substance, but can be fractionated into several active components of different size and different charge. Gel filtration of mononuclear cell supernatants separated the eosinophil-activating activity into a major component of molecular mass of 40 kDa and a minor component of molecular mass of less than 10 kDa. The major component exhibited further heterogeneity on fractionation by high performance liquid chromatography. The bulk of the eosinophil-activating activity could be separated from both colony-stimulating factor (CSF) alpha activity and from tumor necrosis factor (TNF) activity. However, human recombinant CSF alpha (GM-CSF), human recombinant TNF and rabbit tumor necrosis serum all had eosinophil-activating activity when tested against schistosomula. Eosinophils were not activated by interleukin 1, interleukin 2, interferon-alpha, lipopolysaccharide or phorbol myristate acetate.
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PMID:A comparison of eosinophil-activating factor (EAF) with other monokines and lymphokines. 348 22

Previous work identified certain components of the immunological network that had been activated following the adoptive immunotherapy of tumor-bearing mice. The present report shows that part of the activation process involves the IL-1 pathway. Tumor-associated macrophages (TAM) from C57BL/6J mice bearing the immunogenic sarcoma, MCA/76-9, and tumor-bearers injected with cyclophosphamide (CY) or CY plus the intravenous transfer of tumor-sensitized lymphocytes showed relatively high levels of intracellular (IC) IL-1, as demonstrated in the mitogenic and comitogenic assays. Gel chromatography of IC IL-1 and extracellular (EC) IL-1 from TAM induced to secrete IL-1 by stimulation with lipopolysaccharide indicated a single peak of activity of similar molecular size. The active fractions of the EC IL-1 were found to increase in activity as they were diluted to a maximum of 1/64, beyond which IL-1 activity declined. Fractions of the IC IL-1 showed no increased activity on dilution. Filtrates (less than 10 kDa) obtained on concentration of the IC and EC IL-1 samples prior to fractionation were shown to contain an activity (3-5 kDa) that inhibited the uptake of [3H]TdR by thymocytes in the mitogenic and comitogenic assays. Membrane-bound IL-1 activity also was expressed by TAM and this coincided with the previously reported peak Ia expression by these cells. TAM were also shown to induce strong proliferative responses by allogeneic lymphocyte. Systemic amplification of antitumor responses was detected in mice bearing progressing tumors and in those that had received combination therapy as measured both by increases in free IL-1 in the peritoneal cavity and IL-1 within the peritoneal macrophages. These observations indicate that in addition to enhancement of Ia expression, the IL-1 pathway also is activated and amplified systemically in this model system of tumor progression and rejection.
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PMID:Activation of the IL-1 pathway during amplification of immune responses in tumor-bearing mice. 349 84

Alterations in hepatic function are seen in sepsis or multiple-system organ failure. We have hypothesized that Kupffer cells (KCs) within the liver alter the function of contiguous hepatocytes after exposure to septic stimuli. Using an in vitro coculture system, we have found that lipopolysaccharide (LPS) induced a 40% to 60% decrease in cocultured hepatocyte protein synthesis but had no effect on hepatocytes alone. Coculture in the absence of LPS resulted in enhanced hepatocyte protein synthesis proportional to the number of KCs or macrophages (M0s). Conditioned medium (CM) from LPS-triggered coculture or KC alone decreased protein synthesis of hepatocytes whereas CM from hepatocytes alone had no effect. Gel filtration of active M0-CM showing maximal hepatocyte inhibitory activity was present in fractions between 15,000 and 30,000 daltons. This inhibitory activity was inactivated by exposure to 65 degrees C for 30 minutes. Although CM from untriggered M0 did not inhibit hepatocyte protein synthesis, lysates from both LPS-triggered and control M0 were inhibitory. These results show that M0s/KCs exposed to septic stimuli decrease hepatocyte protein synthesis via heat labile, soluble mediator(s) that may already be synthesized within untriggered cells. We hypothesize that soluble M0/KC mediators normally modulate hepatocyte function and that this normal homeostatic control is profoundly altered during sepsis.
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PMID:Further characterization of Kupffer cell/macrophage-mediated alterations in hepatocyte protein synthesis. 373 62

Endotoxin producing bacteria cause disseminated intravascular coagulation (DIC); however, the mechanism of endotoxin action in man is still unclear. Impairment of the fibrinolytic system has been suggested as a contributing mechanism. A single injection of Escherichia coli lipopolysaccharide in rabbits resulted in a marked and prolonged increase of the levels of a fast-acting inhibitor of plasminogen activator (PA-inhibitor) in plasma (from 3.9 +/- 0.7 to 41 +/- 13.2 U/ml after 3 h). Gel filtration studies indicated that inhibition of human tissue-type plasminogen activator (t-PA) by rabbit plasma is accompanied by a change in the elution profile of the activator compatible with the formation of an enzyme-inhibitor complex with an apparent molecular weight of 100,000. Injection of human t-PA (1,500 IU/kg body wt) in endotoxin treated animals resulted in very fast inhibition of t-PA and formation of a similar complex. The half-life of circulating PA-inhibitor activity in rabbits was about 7 min as estimated by donor receiver plasma transfusion experiments. Stimulation of cultured human endothelial cells with endotoxin resulted in enhanced rate of accumulation of PA-inhibitor activity in the culture medium (two- to sevenfold increase). In five patients with septicemia, markedly increased levels of PA-inhibitor (14.3 +/- 15.5 U/ml) as compared with control subjects (1.3 +/- 0.7 U/ml) were observed in plasma. A very strong correlation (r = 0.98) was found between inhibition of t-PA and of urokinase in all conditions, suggesting that this fast-acting inhibitor reacts with both plasminogen activators. These data suggest that the appearance of this fast-acting PA-inhibitor is very sensitive to endotoxin stimulation. The marked increase in the level of PA-inhibitor in blood may contribute to the pathogenesis of DIC in septicemia.
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PMID:Generation in plasma of a fast-acting inhibitor of plasminogen activator in response to endotoxin stimulation. 392 Feb 45

Isolated cell envelopes of Pseudomonas aeruginosa were treated with N,N'-dimethylformamide (DMF) or with ethylenediaminetetraacetate (EDTA). DMF solubilized 73% of the dry weight of the cell envelope, 76% of the protein, 78% of the carbohydrate, and 76% of the phosphorus. Electron microscopy showed that DMF caused extensive alterations in the appearance of the cell envelope with blebs and bleblike vesicles predominating. After incubation with EDTA, the cell envelopes appeared to have lost material, but still retained the cell-like morphology. Analysis of DMF-solubilized proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed 16 protein bands. There were three major proteins that predominated, however, with molecular masses of 43,000 (protein A), 16,500 (protein B), and 72,000 daltons (protein C). Evidence is presented that protein A and protein B are glycoproteins. Gel electrophoresis of EDTA-solubilized material revealed that a number of proteins were released from the cell envelope. However, electrophoresis of an isolated protein-lipopolysaccharide complex released by EDTA showed that protein A and protein B were the major protein components of this complex. These data suggest that protein A and protein B are components of the outer cell wall membrane of P. aeruginosa. There is suggestive evidence that these proteins may play a role in maintaining the structural integrity of the cell envelope. Whether these proteins also have enzymatic activity could not be discerned from the present study, although it is possible that they may be associated with the terminal stages of lipopolysaccharide synthesis.
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PMID:Proteins released from cell envelopes of Pseudomonas aeruginosa on exposure to ethylenediaminetetraacetate: comparison with dimethylformamide-extractable proteins. 463 46

Alkaline treatment of Pseudomonas aeruginosa type 5 lipopolysaccharide (LPS) resulted in reduced toxicity as measured by both the Limulus amoebocyte assay and the rabbit pyrogenicity test. Chemical analysis of the deacylated LPS (D-LPS) revealed that ester-linked fatty acids were removed while the amide-linked fatty acids remained intact. The neutral and amino sugar compositions for native LPS and D-LPS were identical within experimental error. Antigenic determinants for complement-dependent human opsonic antibody were retained under these deacylation conditions. To enhance its immunogenicity, D-LPS was covalently coupled to Pseudomonas pili and the 1,4-diaminobutyl derivatives of Pseudomonas exotoxin A and tetanus toxoid. Quantitative amino sugar analyses revealed that 2.6 and 3.2 mol of D-LPS were covalently bound to aminobutyl Pseudomonas exotoxin A and aminobutyl tetanus toxoid, respectively. Gel electrophoresis data indicated at least 1 mol of D-LPS covalently bound per pilus subunit protein. Initial immunologic data indicated that antibody against D-LPS could be induced when the D-LPS is covalently attached to protein carriers.
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PMID:Preparation and characterization of detoxified lipopolysaccharide-protein conjugates. 616 12

A serologically heterogeneous lipopolysaccharide (LPS) was prepared from B. fragilis IPL E323 by phenol-water extraction and purification by ultracentrifugation. The LPS was split by hydrolysis with 1 per cent acetic acid into an acid-soluble polysaccharide and insoluble material. Gel filtration of the acid-soluble material on Bio-Gel P-60 gave a high-molecular-weight fraction eluted with the void volume (Vo), which was serologically heterogeneous, and low-molecular-weight materials eluted at 2.5 x Vo and 2.7 x Vo. Some material was also eluted at 2.9-3.0 x Vo. The oligosaccharides eluted at 2.5 x Vo and 2.7 x Vo showed an antibody-neutralizing capacity similar to that of the parent LPS. Galactose, glucose and rhamnose were the only sugars present in these fractions. The material eluted at 2.9-3.0 x Vo, which contained the same neutral sugars, but at another molar ratio, was serologically inactive. SImilar results were obtained when LPS from three other B. fragilis strains were treated in the same way.
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PMID:Immunochemical studies of lipopolysaccharide and partially degraded lipopolysaccharide from Bacteroides fragilis IPL E323. 618 42

Antigen-specific, T cell-derived helper factor (ASHF), recognizing alloantigens on chicken red blood cells (CRBC), had previously been shown to trigger an IgM anti-CRBC response in vitro by 2 X 10(3) affinity-enriched B cells. Triggering signals for B cell proliferation were shown to be substituted by ASHF or lipopolysaccharide, and signals for differentiation to IgM production by Thy-1+ cells. In an effort to demonstrate unequivocally antigen specificity of helper factor, secretory products and cell extracts from helper T cells that had been primed by either the B2 or the B13 chicken alloantigens, were purified by antigen affinity and ion exchange chromatography. With each step of purification, antigen-specific biologic activity of ASHF-containing material increased such that ASHF from B2, but not B13, primed helper T cells would help trigger a B2, but not a B13, -specific response and vice versa. Gel filtration of ASHF suggests it to have a m.w. of at least 50,000. Absorption studies showed that ASHF binds to B cells in the absence of antigen. Delivery of the triggering signal requires ASHF to bind simultaneously to both, the cell surface and the antigen. ASHF consists of at least two subunits that may be separated from each other by chelating agents. This yields two biologically inactive fractions, only one of which binds to the nominal antigen. Upon recombining them in the presence of Ca++, full biologic activity is restored.
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PMID:Triggering of affinity-enriched B cells. II. Composition and B cell triggering properties of affinity-purified, antigen-specific, T cell-derived helper factor. 619 16

Murine sarcoma virus-transformed mouse fibroblasts produce potent immunosuppressive factors (ISF) in vitro. The partially purified ISF inhibited thymocyte proliferation induced by concanavalin A or phytohemagglutinin plus lymphocyte activating factor (Interleukin 1), lipopolysaccharide-induced spleen cell proliferation, the in vitro splenic anti-sheep erythrocyte plaque-forming cell response, and the generation of alloantigen-specific cytotoxic T cells. The effect of ISF on thymocyte proliferation was not readily reversible and required only a 4-hr exposure of the thymocytes to ISF to inhibit cell proliferation. Although ISF shares several biochemical properties with a murine sarcoma virus-transformed cell-derived sarcoma growth factor (e.g., acetic acid solubility and sensitivity to dithiothreitol), the two factors could be resolved by gel filtration on Bio-Gel P-60. Two peaks of ISF activity were found with apparent molecular weights of 12,000 and 8000. The results described here support the hypothesis that at least some of the ISF obtained from the serum of tumor-bearing hosts may be released by the tumor cells themselves. In view of the potent in vitro activity of the murine sarcoma virus-transformed fibroblast-derived ISF, it is quite possible that ISF-like molecules may play a role in subverting in vivo tumor rejection processes involving the immune system.
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PMID:In vitro production of immunosuppressive factors by murine sarcoma virus-transformed mouse fibroblasts. 624 26


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