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 terminal step in the maturation of mononuclear cells from circulating monocytes to resident macrophages is accompanied by dramatic changes in cell morphology and physiology. Applying a cultivation system which allows peripheral monocytes to undergo terminal maturation in vitro under absolutely endotoxin-free conditions, we have determined the pattern of expression of a set of eight genes by mRNA phenotyping. The results can be summarized as follows: the two protease inhibitors alpha 1-antitrypsin and alpha 2-macroglobulin show a inverse pattern of expression. alpha 1-Antitrypsin mRNA is repressed, alpha 2-macroglobulin mRNA is strongly induced during maturation to macrophages. Therefore, these two genes are excellent markers of the terminal maturation. In addition, ferritin-light-chain mRNA progressively increases during the course of differentiation, providing a further marker for maturation. Gene expression as a function of activation was studied in mononuclear cells stimulated with bacterial endotoxin (lipopolysaccharide). In monocytes, complement-factor-B, interleukin-1 and interleukin-6 mRNAs are drastically induced upon lipopolysaccharide activation whereas lysozyme RNA is strongly repressed. However, the ability of all four genes to respond to endotoxin was markedly diminished or abolished in mature macrophages, indicating that susceptibility to a certain type of activation may be restricted to a specific stage of maturation. Our data show that mRNA phenotyping is excellently suited for the characterization of the differentiation and activation state of mononuclear phagocytes.
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PMID:Characterization of mononuclear-phagocyte terminal maturation by mRNA phenotyping using a set of cloned cDNA probes. 258 84

Experiments have been carried out to characterize the binding of lysozyme (LZM) to bacteriol lipopolysaccharide (LPS). The formation of LPS.LZM complexes can be readily demonstrated using either physical-chemical separation techniques or a radiolabeled photoaffinity LPS probe. The binding affinity of LZM for LPS has been estimated to be approximately 10(8) liters/mol. Binding of LPS results in loss of LZM enzymatic activity by a noncompetitive inhibition, as assessed by either particulate or soluble substrates. This interaction of LPS with LZM is dictated primarily by hydrophobic interactions and appears to be a general property of both constituents. Binding can be demonstrated with LZM of both human and avian sources, as well as with LPS isolated from a variety of Gram-negative organisms. The addition of LPS to biologically relevant fluids containing LZM results in dose-dependent inhibition of LZM enzymatic activity suggesting that such interactions may have relevance in Gram-negative infections. Finally LZM has been shown to reduce the endotoxic activity of LPS as assessed by gelation of Limulus amoebocyte lysates.
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PMID:Lipopolysaccharide interaction with lysozyme. Binding of lipopolysaccharide to lysozyme and inhibition of lysozyme enzymatic activity. 264 36

The structural features of lipopolysaccharide [LPS] which influence the binding and inactivation of lysozyme have been examined. Binding of polysaccharide-containing LPS (S-LPS) and Ra-Rc-LPS preparations was independent of temperature between 37-50 degrees C; in contrast, binding of Rd-LPS, Re-LPS and lipid A was temperature-dependent. The binding of lysozyme to Rd-LPS and Re-LPS was increased by treatment with mild alkali, which has little detectable effect on binding of lysozyme to S-LPS and Ra-Rc-LPS preparations. Competitive binding experiments using dansylated lysozyme and/or dansylated polymyxin B indicated independent binding sites on the LPS for lysozyme and polymyxin B. These results indicate significant differences between most LPS preparations and lipid A and glycolipid LPS in their interaction with proteins of mammalian origin.
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PMID:Effects of lipopolysaccharide chemotype structure on binding and inactivation of hen egg lysozyme. 269 Dec 50

The effect of complex formation between lysozyme and lipopolysaccharide (LPS) on the immunostimulatory activities of LPS have been investigated in vitro. Three prototype immunostimulatory activities were examined: B-lymphocyte proliferation, B-lymphocyte differentiation and macrophage production of lymphocyte-activating factor activity. Different effects of lysozyme were noted, depending upon the structure of the LPS, even though previous studies have established that all LPS preparations readily bind lysozyme. Both Re-LPS- and lipid-A-dependent immunostimulatory activities were readily inhibited by lysozyme in a dose-dependent fashion. In contrast, S-LPS and Ra-LPS were unaffected in their immunostimulatory activities by lysozyme. These differences were not the result of quantitative differences in LPS binding of lysozyme, or effects of lysozyme on overall binding of LPS to target cells. These data suggest that the factors which dictate the initial interactions between LPS and lymphoreticular cells may not be identical for all LPS preparations and/or purified lipid A.
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PMID:Lipopolysaccharide interactions with lysozyme differentially affect lipopolysaccharide immunostimulatory activity. 269 Dec 51

The effect of bacterial lipopolysaccharide (LPS) on the immune response of adult mice to hen egg lysozyme (HEL) was studied under conditions in which hyporesponsiveness to HEL was induced by: (i) the intravenous injection of syngeneic spleen cells incubated with HEL; (ii) the intravenous administration of soluble HEL, and (iii) the intraperitoneal injection of HEL in IFA. In all cases, mice were immunized by footpad injection of HEL, with or without LPS. The antibody response produced was measured by the number of indirect anti-HEL plaque forming cells (PFC) detected in popliteal lymph nodes. The incorporation of LPS in the immunizing dose of HEL had little effect on the response of controls; however, it resulted in an appreciable increase in the antibody response of all three groups of hyporesponsive mice. Although, after treatment with LPS, the number of PFC detected in mice made tolerant by spleen cell injection approached those of the controls, lower increases in the antibody response were noted for the remaining two groups of hyporesponsive mice.
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PMID:Increase by bacterial lipopolysaccharide of antibody production in mice rendered hyporesponsive to lysozyme. 269 Dec 85

Surface proteins of nine Campylobacter jejuni strains belonging to three different serovia were extracted with lysozyme/ethylenediamine-tetraacetic acid. The preparations bound to isolated murine small intestinal cells and to a membrane fraction (MF) of isolated brush borders obtained by detergent treatment with Triton X-100 and Nonidet P40. Binding was demonstrated by an enzyme-linked immunosorbent assay procedure. Using lipopolysaccharide (LPS)- and flagella-specific antisera the contribution of flagella and LPS, present in the protein preparations, to the total binding to MF was investigated. Only up to approximately 10% of the total binding of each strain was found to be mediated by LPS, 10%-33% of binding was flagella dependent. The preparations of four strains (serovar HS2) bound in a trypsin-sensitive manner (45%-85% reduction), while the others (serovaria HS1 and HS13) were hardly influenced by trypsin treatment. Binding to MF was not impaired by preincubation of the bacterial surface protein preparations with several sugars and lectins.
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PMID:In vitro binding of Campylobacter jejuni surface proteins to murine small intestinal cell membranes. 274 90

The purpose of these studies was to determine if testicular macrophages are capable of bactericidal activity. Testicular macrophages were isolated from adult Wistar rats and studied in vitro. Studies were designed to determine if these cells could kill pathogenic gram-negative organisms and if these cells secreted lysozyme, an enzyme involved with the lysis of the cell wall of gram-positive bacteria. The regulation of lysozyme secretion by hormones and lipopolysaccharide was also studied. The secretion of this enzyme by testicular macrophages was also compared to enzyme secretion by macrophages isolated from other tissues. We also studied the secretion of superoxide anion, which is known to be involved in cytotoxic reactions. It was found that testicular macrophages were capable of killing up to approximately 38% of a virulent encapsulated strain of Klebsiella pneumoniae within 1 h. This process was in part dependent upon the presence of immune serum generated against these organisms but could not be mimicked by control serum or immune serum tested in the absence of macrophages. Testicular macrophages secreted lysozyme in culture for at least 8 days; however, macrophages from the peritoneal cavity and lung secreted significantly more lysozyme under the same conditions. Lipopolysaccharide suppressed lysozyme secretion in a dose-dependent manner, whereas neither follicle-stimulating hormone, testosterone, nor leuteininzing hormone had an effect on lysozyme secretion. Finally, testicular macrophages secreted superoxide anion in a manner similar to peritoneal macrophages. These studies indicate that testicular macrophages have the capability to mount an appropriate defense against pathogenic bacteria by opsonization-dependent phagocytosis, the secretion of lysozyme, and the production of super oxide anion.
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PMID:Bactericidal activity of testicular macrophages. 284 Sep 82

Interleukin-1 (IL-1) and other monocyte products have several important effects on the systemic response to infection in addition to their roles in lymphocyte stimulation. The present studies were carried out to determine whether products of stimulated monocytes activated circulating neutrophils (PMN) to increase expression of receptors for C3b (CR1) and C3bi (CR3), which are necessary for optimal margination, migration, and phagocytosis. Supernatants of human mononuclear cells that had been stimulated with lipopolysaccharide (LPS) or purified protein derivative (PPD) contained both tumor necrosis factor (TNF) and IL-1 and increased CR1 and CR3 expression on isolated PMNs. Supernatants of unstimulated cultures, media alone, or LPS or PPD alone had little or no effect. Supernatant effects were detectable at 1:3,000 final dilution and appeared to have a characteristic slow time course. These supernatants also caused dose- and time-dependent secretion of PMN granular constituents, but maximal receptor expression was accompanied by secretion of less than 10% of the cells' content of lysozyme and less than 16% of the B12 binding protein. Immunoadsorption studies showed that the supernatant's activity could be removed by anti-TNF but not by anti-IL-1. Recombinant IL-1 had no effect on receptor expression, but recombinant TNF increased CR1 and CR3 expression with kinetics similar to the supernatants. These results thus indicate that TNF is the major monocyte product that increases CR1 and CR3 expression on mature blood neutrophils. This would result in increased margination and phagocytic activity and may be an important systemic effect that would help the host eradicate infection.
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PMID:Tumor necrosis factor is the major monocyte product that increases complement receptor expression on mature human neutrophils. 296 77

We examined the arthropathic activity of purified peptidoglycan (PG) fragments derived from (i) lysozyme-resistant, extensively O-acetylated PG from Neisseria gonorrhoeae FA19 (O-PG), and (ii) lysozyme-sensitive, O-acetyl-deficient PG from N. gonorrhoeae RD5 (non-O-PG). Male Lewis rats were injected intradermally in the tail with 200 micrograms of PG emulsified in mineral oil and water (1:1) or with the oil and water emulsion alone (controls). Quantitation of hind paw size indicated that macromolecular PG of various chemical and physical forms induced paw swelling (P versus controls, less than 0.01) that was evident at about day 14 and that reached a maximum at about day 24. PG-mediated paw swelling was accompanied by intense synovitis with some cartilage and bone involvement. The minimal arthropathic dose of soluble macromolecular PG was 20 micrograms per rat. Of particular interest was that macromolecular O-PGs from strain FA19 caused considerably more extensive swelling than did either their RD5 non-O-PG counterparts or the homologous FA19 PG that had been de-O-acetylated by mild alkali treatment. This suggested that the persistence of hydrolase-resistant high-molecular-weight fragments, afforded by extensive O-acetylation, may be important for optimal expression of arthropathic activity. However, oligomeric PG was not an absolute requirement, since even low-molecular-weight fragments, including the anhydro-muramyl-containing disaccharide peptide monomer released by growing gonococci, were also arthritogenic. Experiments employing purified gonococcal lipopolysaccharide indicated that the arthropathic activity of PG preparations was not due to contaminating lipopolysaccharide. Based on the arthritogenicity of gonococcal PG in this model system, we suggest that PG may play a role in the pathogenesis of gonococcal arthritis, and that such an activity might be potentiated by the persistence of hydrolase-resistant O-PG.
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PMID:Arthropathic properties of gonococcal peptidoglycan fragments: implications for the pathogenesis of disseminated gonococcal disease. 308 86

Coxiella burnetii, the etiological agent of Q fever, possesses immunomodulatory activity which positively and negatively regulates host immune responses. We wish to determine the Coxiella strain differences and the chemical nature of cellular components suppressing lymphocyte responsiveness. The bacterial components responsible for the immunomodulatory activity are associated with phase I cells. In its natural state, the phase I cell-associated, immunosuppressive complex (ISC) was resistant to chemical and enzymatic treatment. The ISC was inactivated and rendered accessible by chloroform-methanol (CM) (4:1) extraction of phase I cells which produced a CM residue (CMRI) and CM extract (CME). The suppressive components in either CMRI or CME did not induce ISC activity in the host when injected separately. Reconstitution of the CMRI with CME prior to injection produced the same pathological reactions characteristic of phase I cells. The CMRI suppressive component was sensitive to alkali, acid, periodate, lysozyme, and neuraminidase, but resistant to lipase and protease. An active component of CMRI was attached to the cell matrix by disulphide bonds. The amphipathic, lipophilic, CME suppressive component was ubiquitously distributed in procaryotes and eukaryotes because ISC activity of CMRI was regained after association with reagent-grade lipids and different CMEs. The ISC was expressed by phase I strains with smooth lipopolysaccharide (LPS) but not by phase II strains with rough LPS. Phase I heart valve strains carrying significant amounts of rough LPS did not express all of the biological properties of the ISC. The LPS molecule induced immune enhancement without immunosuppression. Thus, expression of the ISC showed strain variation and may be under genetic control. The complete details of the chemical composition and active components of the ISC should prove useful for biological-response-modification studies.
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PMID:Immune modulation by Coxiella burnetii: characterization of a phase I immunosuppressive complex differentially expressed among strains. 317 Nov 7


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