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

Thymocytes from Balb/C mice were activated in vitro by Zn++ as noted by the several-fold increases in 3H-thymidine incorporation at 144 h of culture. Thymocyte activation by Zn++ required the presence of 2-mercaptoethanol (2-ME) and bacterial lipopolysaccharide (LPS) in concentrations as low as 1.0 ng/ml. Thymocytes were not stimulated by these agents in the absence of Zn++. Bovine serum products, thought to contain trace amounts of LPS, appeared to satisfy this LPS requirement. Interleukin 1 (IL 1) could not replace LPS as a cofactor. Thymocytes did not respond to Hg++ under the culture conditions used here. Thymocyte subpopulation studies showed that cell preparations enriched for peanut lectin receptor-negative, mature thymocytes were activated by Zn++ and required LPS for the response.
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PMID:Heavy-metal mitogenesis: thymocyte activation by Zn++ requires 2-mercaptoethanol and lipopolysaccharide as cofactors. 349 67

Interleukin-2, a product of helper T cells, is essentially involved in the regulation of cell-mediated immunity. Two monocyte-derived factors, interleukin-1 and prostaglandin E2, influence interleukin-2 synthesis with opposite actions. To analyse immunoregulatory function in HBsAg-positive chronic active hepatitis, T cell subsets in peripheral blood and the levels of interleukin-2, interleukin-1 and prostaglandin E2 in supernatants from lectin- or lipopolysaccharide-activated peripheral mononuclear cell cultures were determined in 16 healthy controls and 33 patients with chronic active hepatitis B. Interleukin-2 activity was comparable to the controls in patients without delta infection who had seroconverted to anti-HBe (group 1), but it was significantly reduced in both HBeAg-positive subjects (group 2) (P less than 0.05 vs. controls and group 1) and those cases with positive delta markers (group 3) (P less than 0.01 and less than 0.05 vs. controls and group 1, respectively). In group 3, interleukin-2 was similarly diminished in both anti-HTLV-III-positive and -negative cases as well as in HBeAg- and anti-HBe-positive subjects. Notwithstanding the changes in interleukin-2 activity, no significant differences in the number of T4 cells, or in the levels of either interleukin-1 or prostaglandin E2, were found among the various groups of subjects studied. However, in those groups with reduced interleukin-2 activity an increased number of T8 cells was observed. It is suggested that the low levels of interleukin-2 found in the replicative phase of chronic active hepatitis B and in delta superinfection reflect a disturbed immunoregulation that may contribute to persistent viral replication in these two conditions.
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PMID:Interleukins in chronic active hepatitis B. Relationship with viral markers. 349 50

Antigen 60 (A60) is the main thermostable immunogen of both 'old tuberculin' (OT) and 'purified protein derivative' (PPD), known reagents for cutaneous tests in tuberculosis. It is recognized by bidimensional immunoelectrophoresis with anti-BCG antiserum, where it appears as the less mobile component. A60 was prepared from the cytoplasm of Mycobacterium bovis BCG, and purified by exclusion gel chromatography and lectin affinity chromatography. Labelled A60 was obtained by radioiodination and used for a radioimmunoassay. Composition of A60 was explored by use of organic solvents, chemicals and enzymes. It contained two fractions of free and bound lipids, as well as protein and polysaccharide moieties. After removal of both free and bound lipid fractions, the core still retained the ability to form immunoprecipitinogen lines with anti-BCG antiserum. The lipopolysaccharide and lipo-protein moieties of A60, as well as the free lipid fraction, were also complexed by antibodies. It is concluded that A60 is a lipopolysaccharide-protein complex of 10(6) to 10(7) daltons, which is a major immunogenic component of mycobacterial cytoplasm. The detailed structure of this antigen, its immunological properties, and its use for an ELISA type immunoassay for tuberculosis are described in two other publications.
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PMID:Preparation and properties of antigen 60 from Mycobacterium bovis BCG. 354 72

Human lectin purified from placenta induced release of cytotoxin from a murine macrophage cell line and human peritoneal monocytes. This activity was not due to contamination of the lectin preparation with lipopolysaccharide.
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PMID:Release of cytotoxin by macrophages on treatment with human placenta lectin. 374 25

Salmonella telaviv, Salmonella tranoroa, and Salmonella illinois were examined for their ability to interact with 15 purified lectins of known sugar specificity. The only interaction observed was between the lectin of Maclura pomifera and S. telaviv. M. pomifera lectin specifically agglutinated suspensions of S. telaviv and precipitated with its purified lipopolysaccharide and isolated lipid A free O polysaccharide. Quantitative inhibition assays showing methyl-alpha-D-galactopyranoside and N-acetyl-D-galactosamine to be potent inhibitors of Maclura lectin precipitation by S. telaviv O polysaccharide suggest that the interaction is mediated by D-galactose or N-acetyl-D-galactosamine units of bacterial polysaccharide structure, or both.
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PMID:Interaction of Salmonella telaviv with Maclura pomifera lectin. 383 92

RU 41.740, a glycoprotein extract from Klebsiella pneumoniae, is a polyclonal B cell activator in the thymus-independent category, and both RU 41.740 and its fraction F1 induce the production of interleukin 1 (IL 1). RU 41.740 alone appears to have no direct effect on T-enriched cells. However, we show here that when given in conjunction with concanavalin A (Con A), RU 41.740 enabled nylon wool-passed T cells, which had been accessory cell depleted and lost responsiveness to Con A, to proliferate in response to Con A. Analysis of this observation indicated that RU 41.740 probably acted via a residual accessory cell population and that contact of this cell with the T cell was necessary for Con A activation of the T cell. Because both lectin/antigen and a source of IL 1 are required to stimulate accessory cell-depleted T cells, the mechanism of action of RU 41.740 in this system may be by induction of IL 1 from residual accessory cells in the nylon wool-passed, T-enriched cell population. However, two other agents that stimulate IL 1 production, lipopolysaccharide (LPS) and F1, do not enable T-enriched cells to respond to Con A in this system.
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PMID:Influence of RU 41.740, a glycoprotein extract from Klebsiella pneumoniae, on the murine system. II. RU 41.740 facilitates the response to Con A in otherwise unresponsive T-enriched cells. 388 53

Escherichia coli strains from' serotypes O86, 0128 and O111 varied in their reactivity with Pseudomonas aeruginose lectins (PA-I with D-galactose specificity and PA-II which binds L-fucose, D-mannose, L-galactose and D-fructose). Generally, cells of O86 strains were agglutinated by PA-I, but not by PA-II, and those of O128 serotype were agglutinated by PA-II, and not by PA-I. Adsorption tests showed that cells of E. coli O86 strains adsorb PA-I to a greater extent than PA-II, while most E. coli O128 strains adsorbed higher amounts of PA-II. Cells of E. coli O111B4 which were not agglutinated by either Pseudomonas lectin could still adsorb both. Boiling of O86 and O128 cells frequently enhanced their agglutinability as well as their lectin adsorption capacity. The agglutinability enhancement was somewhat more prominent in boiled stationary phase cells than in log phase cells probably due to late synthesis of the O antigen components concomitantly with the heat-sensitive components (K antigens) which masked them. PA-I agglutinating activity was inhibited by the lipopolysaccharide (LPS) extracted from E. coli O86 cells, while PA-II was inhibited by the LPS extracted from E. coli O128 cells. These findings indicate that the receptors to the Pseudomonas lectins probably reside in the terminal part of the O-specific-polysaccharide of the LPSs of these bacteria.
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PMID:Effects of growth phase and boiling of enteropathogenic Escherichia coli strains on their interaction with Pseudomonas aeruginosa lectins. 393 24

Two variables of immune status were measured in vitamin A-deficient (A-), vitamin A-sufficient pair-fed (A + PF), and healthy control (A+) rats to examine the mechanisms of immune regulation by vitamin A. Parallel samples were run in bovine fetal serum (BFS)-containing medium and serum-free medium to control BFS-origin vitamin A in the cultures. Splenocytes derived from A- rats showed significantly depressed blastogenic response to all lectins tested in both mediums when compared with responses of A + PF and A+ rats. The splenocyte blastogenic response of A + PF rats was significantly lower than that of A+ (control) rats only when cultured in BFS medium and stimulated by lentil lectin, lipopolysaccharide, or concanavalin A mitogens. Thymic lymphocyte blastogenic transformation assays were equivocal. Splenic immunosuppression could not be linked to significant reductions in surface glycoprotein receptor availability, since splenocytes of A- rats, as well as thymocytes, were capable of binding fluorescein isothiocyanate-conjugated lectins in the same capacity as splenocytes of A+ and A + PF rats. The combination of depressed cellular function and adequate lectin binding to viable cells implies that the regulation of immunohomeostasis by vitamin A was achieved through intracellular mechanisms, possibly selective genomic expression.
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PMID:Assessment of lymphocyte function during vitamin A deficiency. 396 87

The B lymphocyte mitogens, bacterial lipopolysaccharide (LPS), pokeweed lectin, and tuberculin, induced proliferation in density-inhibited monolayer cultures of chick embryo fibroblasts. The stimulation was seen both as an early increase in sugar uptake and cell volume and later as an increase in thymidine incorporation and cell number. The concentration of LPS maximally stimulating fibroblasts was remarkably low, about 0.1-1 ng/ml. LPS preparation with very different sugar chains gave quite similar results indicating that the architecture of the hydrophilic carbohydrate part is not critical for the mitogenic effect.
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PMID:Mitogenic effect by lipopolysaccharide and pokeweed lectin on density-inhibited chick embryo fibroblasts. 476 51

The lipopolysaccharide (LPS) from Rhizobium trifolii 0403 was isolated at different stages of growth and was examined for its (i) ability to bind a white clover lectin (trifoliin A), (ii) immunochemical properties, and (iii) composition. There was significantly more binding of trifoliin A to purified LPS and cells in the early stationary phase than to cells in the exponential phase. Immunofluorescence and enzyme-linked immunosorbent assays indicated that new antigenic determinants of the LPS appeared for brief periods on cells at the end of the lag phase and again at the beginning of the stationary phase. These new antigens were not detected on cells in midexponential or late stationary phase. Monovalent fragments of immunoglobulin G antibodies raised against the unique antigenic determinants in the LPS competitively blocked the binding of trifoliin A to cells in the early stationary phase. Gas chromatographic analysis showed that the relative quantity of several glycosyl components in the LPS increased as the culture advanced from the midexponential to the early stationary phase. In addition, LPS from cells in the early stationary phase had a higher aggregate molecular weight. Quinovosamine (2-amino-2,6-dideoxyglucose) was identified by combined gas chromatography-mass spectrometry as a sugar component of the LPS which had not been previously reported. D-Quinovosamine, N-acetyl-D-quinovosamine, and its n-propyl-beta-glycoside were effective hapten sugars which inhibited the binding of trifoliin A, anti-clover root antibody, and homologous antibody to these new determinants in the LPS. White clover plants had more infected root hairs after incubation with an inoculum of cells in the early stationary phase than after incubation with cells in the midexponential phase. The profound influence of the growth phase on the composition of lectin-binding polysaccharides of Rhizobium may be a major underlying cause of conflicting data among laboratories testing the lectin-recognition hypothesis. In addition, these chemical modifications may reflect mechanisms which regulate Rhizobium-root hair recognition in this nitrogen-fixing symbiosis.
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PMID:Growth-phase-dependent immunodeterminants of Rhizobium trifolii lipopolysaccharide which bind trifoliin A, a white clover lectin. 617 Jun 30


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