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

The immune response of mice to the alpha-l-6 epitope of dextran (Dx) B512 was found to be under genetic control. The congenic mouse strains A, A.CA, A.SW, A.TH, and A.TL exhibited a specific defect in their response to alpha-l-6. Also strain CBA/N was unresponsive to alpha-1-6, but the mechanism of unresponsiveness was found to be different. Unresponsiveness to alpha-l-6 in congenic A strains was not due to suppressor cells. Although these strains failed to respond to the alpha-l-6 epitope, they responded strongly to the hapten Fluorescein isothiocyanate (FITC) conjugated to Dx, indicating that the Dx can function as an efficient carrier in these strains. Dx was a potent polyclonal B-cell activator in congenic A strains as well as in high responder strains. Polyclonally-activating concentrations of lipopolysaccharide (LPS) failed to induce the synthesis of anti-alpha- l-6 antibodies in congenic A strains, although antibodies of all other specificities studied were produced. However, in high responder strains, LPS induced the synthesis of anti-alpha-l-6 antibodies. It was concluded that congenic A strains do not express V genes coding for antibodies against alpha-l-6. In contrast, strain CBA/N failed to respond to both the alpha-l-6 and FITC epitope on Dx, whereas they could respond to FITC conjugated to horse erythrocytes. Dx induced a very small, if any, polyclonal antibody response in B cells from CBA/N mice or male CBA/N x DBA hybrids, whereas Dx was a very potent polyclonal B-cell activator in female hybrids. It is concluded that CBA/N mice are nonresponders to Dx or haptenated Dx, because the cell population that can respond to the polyclonal B-cell activating properties of Dx is severely depleted.
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PMID:Immunological unresponsiveness to thymus-independent antigens: two fundamentally different genetic mechanisms of B-cell unresponsiveness to dextran. 30 86

A high-performance liquid chromatographic method was developed for resolving heterogeneous preparations of fluorescently labelled endotoxin derived from Escherichia coli (Serotype 0111:B4) into separate lipopolysaccharide sub-groups. The endotoxin was chromatographed on an analytical gel permeation column using a mobile phase of acetonitrile (20%, v/v) and 100 mM phosphate buffer (pH 7.75). Four fluorescent peaks were resolved, representing sub-groups of markedly different molecular sizes. Three of the four sub-groups contained the core polysaccharide 2-keto-3-deoxyoctonate, confirming that they contained lipopolysaccharide. Fluorescein isothiocyanate (FITC)-labelled endotoxins derived from Vibrio cholerae and Salmonella minnesota chromatographed using the same system eluted with distinctly different patterns of peaks from each other and from E. coli. Extraction of E. coli FITC-endotoxin from a buffer solution using a phenol-diethyl ether method and subsequent chromatography allowed the determination of three of the four fluorescent sub-groups over the concentration range 1-15 micrograms/ml.
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PMID:High-performance liquid chromatographic method to resolve and determine lipopolysaccharide sub-groups of Escherichia coli endotoxin in isolated perfused rat liver perfusate. 161 51

Video-intensification fluorescence microscopy has been used to study the cell surface distribution of the complement receptor (CR) for C3bi (CR3) on human neutrophils. Fluorescein- or rhodamine-labeled monoclonal IgG or Fab fragments of antireceptor antibody were used as probes of receptor localization. C3bi receptors are uniformly distributed on untreated cells. Glass coverslips were coated with lipopolysaccharide (LPS) and serum was added; the serum deposits complement components, including C3bi, on the surface. When neutrophils were adherent to these coverslips, receptors were found in large clusters, and a fraction of the fluorescence remained uniform. Double-labeling studies were conducted by first labeling with anti-CR3 followed by attachment to LPS/serum-treated slides. This, in turn, was followed by labeling with the antibody conjugated to a second fluorophore. These studies revealed that the CR3 clusters were predominantly new antigenic sites exposed after attachment to the LPS/serum-treated slides. To determine the contribution of granule-associated CR3, we have studied neutrophils defective in receptor up-regulation, neutrophil cytoplasts, and a stimulator of granule release, A23187. Neutrophils from a patient with specific granule deficiency were found to be defective in granular CR3 and did not form clusters on C3-modified surfaces. The patient's neutrophils were defective in CR3 up-regulation and enzyme release as shown by fluorescence flow cytometry and gelatinase release, respectively. Cytoplasts also failed to show CR3 clusters on LPS/serum-treated coverslips. Furthermore, neutrophils treated with A23187 demonstrated numerous CR3 clusters. We suggest that formation of CR3 membrane domains during immune recognition requires the participation of intracellular granules. We speculate that these domains are formed by fusion of CR3-bearing granules at local sites of adhesion.
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PMID:Neutrophil C3bi receptors: formation of membrane clusters during cell triggering requires intracellular granules. 296 Jun 85

The ability to clone hapten-specific B cells in agar and to subsequently trigger their clonal progeny to antibody synthesis was investigated. Fluorescein (FL) specific B cells were purified on FL-gelatin dishes and cultured in semisolid agar for 6 to 7 days; individual colonies were then picked for restimulation in microculture. FL-specific B cells could be cloned as efficiently as unpurified splenic B cells. The number of colonies formed depended on the presence of sheep erythrocytes (SRBC) or E. coli lipopolysaccharide (LPS) in the cultures. An additive number of colonies were observed with SRBC + LPS compared to that of SRBC or LPS alone. The colonies obtained from SRBC-containing cultures were stimulatable at high frequency by various FL-conjugated antigens to yield anti-FL PFC. However, colonies grown with LPS as the only additive were not stimulatable by any of the antigens tested. On the other hand, addition of M phi or SRBC as additional "mitogens" along with LPS in the agar resulted in progeny colonies that could respond in vitro. Although M phi did not increase the number of colonies, their presence enhanced the size and in some cases the frequency of stimulatable colonies. These data complement earlier observations in suggesting that different B cell subpopulations may grow under different cloning conditions. Moreover, the ability to stimulate the clonal progeny of single B cells to antibody synthesis should permit further definition of triggering and tolerance events at the single-cell level.
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PMID:Hapten-specific murine colony-forming B cells: in vitro response of colonies to fluoresceinated thymus independent antigens. 616 21

B cell subpopulations were studied by using B cell cloning procedures and an in vitro tolerance induction model. Fluorescein- (FL) specific B cells from normal spleens were isolated by using FL gelatin plates and were then cultured in semisolid agar in the presence or absence of tolerogen. Hapten-specific cells grew in soft agar to form discrete colonies. Colony growth is dependent on "mitogens" present in agar, sheep red blood cells (SRBC), and lipopolysaccharide (LPS). For example, SRBC plus LPS potentiate the growth of an increased number of colony-forming B cells (CFU-B) compared to either additive alone. These CFU-B could be triggered by a specific antigen to yield plaque-forming cells (PFC). With tolerogen (FL-sheep gamma-globulin) present in the agar, the number of FL-specific CFU-B was reduced by 25 to 50%. The ability of the remaining colonies to form PFC upon antigenic stimulation was also reduced. This reduction in CFU-B numbers, however, was observed only when the agar contained both SRBC and LPS as mitogenic potentiators of growth; no effect of tolerogen on CFU-B numbers was seen when cells were grown with either additive alone. Interestingly, the effect of tolerogen on CFU-B numbers was abrogated when peritoneal macrophages, in addition to SRBC plus LPS, were present during cloning. It is postulated that unique subpopulations of B cells form colonies under varied cloning conditions and that those CFU-B grown with SRBC plus LPS display an increased sensitivity to growth inhibition by tolerogen.
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PMID:Hapten-specific murine colony-forming B cells. II. Delineation of a tolerogen-sensitive subpopulation of colony-forming B cells. 616 98

The growth of a pleiotropic membrane mutant of Salmonella typhimurium with modified lipopolysaccharide composition was found to be strictly dependent on the peptone component of complex media. Nutritional Shiftdown into minimal media allowed growth for three to four generations. Of 20 commercial peptones, only enzymatic digests supported growth to varying degrees. Neither trace cations, amino acids, vitamins, carbohydrates, lipids, glutathione, polyamines, carbodimides, nor synthetic peptides stimulated growth; however, cells still metabolized carbohydrates, and amino acid transport systems were shown to be functional. A tryptic digest of casein was fractionated into four electrophoretically different peptide fractions of 1,000 to 1,200 molecular weight which supported growth to varying degrees. The best of these was further fractionated to two highly hydrophopic peptides. N-terminal modifications eliminated biological activity. Fluorescein-conjugated goat antibody to rabbit immunoglobulin G was used as a probe to detect antipeptide antibody-peptide complexes on membrane preparations. Cells grown on peptone distributed the peptide into both inner and outer membranes. The peptide could be removed with chaotropic agents, and cells had to be pregrown in peptone-containing media to bind the hydrophobic peptide. The gene (hyp) responsible for peptide auxotrophy was mapped at 44 to 45 units by conjugation.
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PMID:Hydrophobic peptide auxotrophy in Salmonella typhimurium. 702 54

Fluorescein isothiocyanate (FITC) was found to stain cytoplasmic granules of avian heterophilgranulocytes. In tissue sections, the fluorescent granulocytes were predominantly distributed adjacent to trabecular bones. The fluorescein stained granulocytes were abundant in synovial fluids of chickens with synovitis. A significant correlation was observed in the percent of fluorescein labeled granulocytes in blood smears and the percent of heterophils determined using an automated counting method, in unstained blood from normal and Escherichia coli-infected turkeys. The fluorescein-binding heterophils purified from chickens showed a time dependent increases in the oxidation of 2',7'-dichlorofluorescin diacetate (DCF-DA) and the reduction of nitroblue tetrazolium (NBT) which were indicative of changes in oxidative burst in response to phorbol 12-myristate 13-acetate (PMA), Salmonella typhimurium lipopolysaccharide (LPS), and zymosan A (ZA). These heterophil-activating agents, also, caused significant degranulation at 16 h post-treatment, as indicated by the loss fluorescence. There were microscopically visible alterations in the cell shapes and a decrease in the density of granules due to treatment with LPS, PMA or ZA. In addition, these cells also showed phagocytic response which was evident at 30 min of incubation with fluorescent latex particles. Both chicken and turkey heterophils produced interleukin-6 in vitro at 24 h in response to LPS but not to PMA, FMLP or ZA. The chicken heterophils showed spontaneous production of matrix metalloproteinases (MMP) which was significantly enhanced by treatment with LPS, PMA, and ZA; however, LPS appeared to be most effective in inducing MMP production. These results demonstrate that the functions of heterophils can be differentially regulated by different activating agents and the fluorescein binding property of these cells may be useful for their histochemical identification.
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PMID:Fluorescein isothiocyanate staining and characterization of avian heterophils. 965 33

The activation of monocytes and macrophages induced by lipopolysaccharide has been shown to contribute to the binding of lipopolysaccharide and lipopolysaccharide-binding protein complex to the cell surface CD14 molecule. To clarify the mechanism of the lipopolysaccharide-induced modulation of the function of gingival fibroblasts, we investigated the effect of anti-CD14 on interleukin 6 (IL-6) production on human gingival fibroblasts in vitro. Immunochemical staining revealed weak positivity for CD14 on fibroblasts from healthy gingiva, while strong positivity for CD14 was found on fibroblasts from inflamed gingiva. Western blot profiles of the fibroblasts and monocytes showed a CD14-positive reaction at 55 kDa. Fluorescein isothiocyanate-conjugated Escherichia coli lipopolysaccharide bound to fibroblasts more strongly in the presence of 10% fetal bovine serum than without serum. This binding, as well as IL-6 production, was blocked by anti-CD14 monoclonal antibody. The results showed that CD14 was present on human gingival fibroblasts, which suggests that lipopolysaccharide modulation of gingival fibroblast function depends on CD14.
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PMID:Immunochemical detection of CD14 on human gingival fibroblasts in vitro. 1009 40

Bacterial lipopolysaccharide (LPS) is an important agent of induction of ocular pathology following corneal injury or wearing of contaminated contact lenses. The mechanism of LPS uptake through the corneal epithelium is unclear, and the role played by inflammatory cells in this phenomenon has not been previously assessed. Fluorescein isothiocyanate-labeled LPS from Escherichia coli was deposited onto the abraded corneas of New Zealand White rabbits. Epifluorescence microscopy of living excised corneas revealed diffuse LPS staining in the epithelial and stromal layers only in the vicinity of the abrasion. In addition, specific cellular uptake of LPS was suggested by fluorescence staining of cells along the abrasion site. In a second series of experiments, an anti-CD18 polyclonal antibody was used to block infiltration of polymorphonuclear neutrophils (PMN) into the cornea. In these experiments, a diffuse distribution of fluorescent LPS was still observed along the abrasion, but the specific cellular uptake was abolished. The findings indicate that LPS enters the cornea via diffuse penetration at sites of injury and that specific cellular uptake of LPS occurs within the cornea via PMN which have migrated into the damaged tissue.
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PMID:Lipopolysaccharide entry in the damaged cornea and specific uptake by polymorphonuclear neutrophils. 1067 99

Polymyxin B, a cationic cyclic decapeptide antibiotic, is well known to bind endotoxin and to neutralize its toxicity. Based on this principle, polymyxin B was immobilized on the chloroacetamidomethylated polystyrene fiber that is reinforced by polypropylene. The adsorbing capacity of the obtained fibers (polymyxin B immobilized fiber [PMX-F]) was evaluated on endotoxin and other serum components in serum and on heparin in phosphate-buffered saline. Fluorescein isothiocyanate-labeled or tetramethylrhodamine isothiocyanate-labeled lipopolysaccharide (LPS) was used as endotoxin. The measurement of the fluorescence intensity showed that PMX-F adsorbed these LPSs depending on their concentration and on amount. The adsorption of endotoxin was confirmed by desorption of LPS from PMX-F as well. PMX-F adsorbed serum amyloid protein A besides LPS, but neither C-reactive protein nor low-density lipoprotein. The adsorbing property of heparin was low.
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PMID:Removal of endotoxin in blood by polymyxin B immobilized polystyrene-derivative fiber. 1198 49


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