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PubMed1988

Heterogeneity of lipopolysaccharides from Pseudomonas aeruginosa: analysis of lipopolysaccharide chain length.

Lipopolysaccharide (LPS) from smooth strains of Pseudomonas aeruginosa 503, PAZ1, PAO1715, PAO1716, and Z61 was fractionated by gel filtration chromatography. LPS samples from the first four strains, all PAO1 derivatives, separated into three major size populations, whereas LPS from strain Z61, a Pac K799/WT mutant strain, separated into two size populations. When column fractions were applied to sodium dodecyl sulfate-polyacrylamide gels in their order of elution, molecules of decreasing size were resolved, and the ladder of molecules with different-length O antigens formed a diagonal across the gel. The LPS from the PAO1 derivatives contained two distinct sets of bands, distinguished on the gels as two sets of diagonals. The set of bands with the faster mobility, the B bands, was found in column fractions comprising the three major amino sugar-containing peaks. In the sample from strain 503, a fourth minor peak which contained B bands was resolved. The slower-moving set of bands, the A bands, were recovered in a minor peak. LPS from strain Z61 contained only one set of bands, with the higher-molecular-weight molecules eluting from the column in a volume similar to that of the B bands of the PAO1 strains. Analysis of the fractions of LPS from all strains indicated that less than 8% of the LPS molecules had a long, attached O antigen. Analysis of the peak that contained mainly A bands indicated a lack of reactive amino sugar and phosphate, although heptose and 2-keto-3-deoxyoctulosonic acid were detected. Reaction of isolated fractions with monoclonal antibody specific for the PAO1 O-antigen side chain indicated that only the B bands from the PAO1 strains were antigenically reactive. The bands from strain Z61 showed no reactivity. The data suggest that the A and B bands from the PAO1 strains are antigenically distinct. We propose that PAO1 strains synthesize two types of molecules that are antigenically different.

Antigens, Bacterial↗

PubMed2003

Phosphorylation of the lipid A region of meningococcal lipopolysaccharide: identification of a family of transferases that add phosphoethanolamine to lipopolysaccharide.

A gene, NMB1638, with homology to the recently characterized gene encoding a phosphoethanolamine transferase, lpt-3, has been identified from the Neisseria meningitidis genome sequence and was found to be present in all meningococcal strains examined. Homology comparison with other database sequences would suggest that NMB1638 and lpt-3 represent genes coding for members of a family of proteins of related function identified in a wide range of gram-negative species of bacteria. When grown and isolated under appropriate conditions, N. meningitidis elaborated lipopolysaccharide (LPS) containing a lipid A that was characteristically phosphorylated with multiple phosphate and phosphoethanolamine residues. In all meningococcal strains examined, each lipid A species contained the basal diphosphorylated species, wherein a phosphate group is attached to each glucosamine residue. Also elaborated within the population of LPS molecules are a variety of "phosphoforms" that contain either an additional phosphate residue, an additional phosphoethanolamine residue, additional phosphate and phosphoethanolamine residues, or an additional phosphate and two phosphoethanolamine residues in the lipid A. Mass spectroscopic analyses of LPS from three strains in which NMB1638 had been inactivated by a specific mutation indicated that there were no phosphoethanolamine residues included in the lipid A region of the LPS and that there was no further phosphorylation of lipid A beyond one additional phosphate species. We propose that NMB1638 encodes a phosphoethanolamine transferase specific for lipid A and propose naming the gene "lptA," for "LPS phosphoethenolamine transferase for lipid A."

Amino Acid Sequence↗

PubMed1978

The lipopolysaccharide (R type) as a common antigen of Neisseria gonorrhoeae. II. Use of hen antiserum to gonococcal lipopolysaccharide in a rapid slide test for the identification of N. gonorrhoeae from primary isolates and secondary cultures.

An antiserum has been prepared in hens to R-type gonococcal lipopolysaccharide (LPS) and used in a simple slide-agglutination test for the identification of Neisseria gonorrhoeae. Anti-LPS serum agglutinated gonococcal cells representative of the four colony types of N. gonorrhoeae. Absorption of the antiserum with LPS removed the agglutinating activity. Secondary cultures (1120) were tested without observation of the colony type and all were agglutinated. No agglutination occurred with strains of Neisseria meningitidis, Neisseria lactamica, non-pathogenic Neisseria. Pseudomonas aeruginosa, Branhamella catarrhalis, or with species of lactobacilli and Acinetobacter. Cross-reactivity of the antiserum occurred with some streptococci. The anti-LPS serum was used to identify N. gonorrhoeae in primary isolates from the cervix, urethra, and pharynx. Of 251 gonococcal isolates tested, 249 were agglutinated by the antiserum, while all of the corresponding second cultures were agglutinated. The antiserum did not agglutinate N. meningitidis found in primary isolates from pharyngeal specimens. Anti-LPS hen serum should be useful for the rapid identification of N. gonorrhoeae in primary isolates or secondary cultures.

Agglutination Tests↗

PubMed2000

Somatostatin and substance P induced in vivo by lipopolysaccharide and in peritoneal macrophages stimulated with lipopolysaccharide or interferon-gamma have differential effects on murine cytokine production.

We have investigated whether lipopolysaccharide (LPS) induces substance P (SP) and somatostatin (SOM) in popliteal lymph nodes in vivo and whether macrophages are a source of SP and SOM in vitro. We have also investigated the effect of SP and SOM treatment on the production of cytokines. SP reached a maximum 3 days after injection of LPS (100 microg/footpad) and then declined. SOM expression after LPS injection reached a maximum at 5-7 days. Stimulation of thioglycolate-elicited peritoneal macrophages with LPS (20 microg/ml), recombinant interferon-gamma (rIFN-gamma, 100 U/ml), and LPS plus rIFN-gamma induced SOM and SP. Thioglycolate-elicited, unstimulated peritoneal macrophages also synthesized these peptides. SOM (10(-12)-10(-8) M) significantly inhibited IL-6 and IFN-gamma production, whereas SP at those concentrations enhanced cytokine production by activated lymphocytes and macrophages. These findings suggest that neuropeptides which originate from macrophages and nerve fibers act as immunomodulators to mediate changes in the pattern of cytokine production.

Animals↗

PubMed1990

Adaptation to bacterial lipopolysaccharide controls lipopolysaccharide-induced tumor necrosis factor production in rabbit macrophages.

These experiments provide an explanation for the observation that two intravenous injections of lipopolysaccharide (LPS) spaced 5 h apart in rabbits cause tumor necrosis factor/cachectin (TNF) levels to rise in the blood only after the first LPS injection. Herein we show that treatment of elicited peritoneal exudate rabbit macrophages (PEM) with two doses of LPS given 9 h apart results in a marked reduction in TNF production by the second LPS exposure. This state of hyporesponsiveness is a result of adaptation to LPS, is induced by LPS concentrations that are 1,000-fold less than required to induce TNF production (picograms vs. nanograms), is characterized by a decrease in LPS-induced TNF mRNA without any change in TNF mRNA half-life, is not changed by including indomethacin in cultures, and is specific for LPS since LPS-adapted cells display a TNF response to heat-killed Staphylococcus aureus that is at least as good as that observed in control PEM.

Adaptation, Physiological↗

PubMed1995

Bacterial lipopolysaccharide-mediated fetal death. Production of a newly recognized form of inducible cyclooxygenase (COX-2) in murine decidua in response to lipopolysaccharide.

Maternal infection is a cause of spontaneous abortion and preterm labor in humans, but the pathophysiology is unclear. We hypothesized that eicosanoids play an important role in infection-driven pregnancy loss. To investigate this hypothesis, we administered lipopolysaccharide (LPS) to pregnant C3H/HeN mice and found that LPS administration caused fetal death in a dose-dependent fashion. Pretreatment with indomethacin significantly decreased the proportion of fetal death from 83% to < 25% in mice injected with 10 micrograms of LPS. Also, decidual explants from LPS-treated mice produced significantly more inflammatory eicosanoids, including prostaglandins E2 and F2 alpha and thromboxane B2, than controls. We investigated the regulatory mechanisms responsible for increased decidual prostanoid production in response to LPS. Western and Northern blots demonstrated that decidual protein and mRNA levels of a recently recognized highly inducible form of cyclooxygenase, COX-2, were substantially increased in mice treated with LPS. Induction of COX-2 was rapid: mRNA was detected 30 min after LPS injection. In contrast, another form of cyclooxygenase, COX-1, was only minimally induced in response to LPS. Our data indicate that LPS induces decidual prostanoid production via increased COX-2 expression. Since LPS-mediated fetal death is markedly diminished by pretreatment with indomethacin, COX-2-mediated eicosanoid production is likely a key pathophysiologic event in LPS-mediated fetal death.

Abortion, Spontaneous↗

PubMed1988

Lipopolysaccharide-stimulated PGE2 release from human monocytes. Comparison of lipopolysaccharides prepared from suspected periodontal pathogens.

Lipopolysaccharides (LPS) prepared from the suspected periodontal pathogens Actinobacillus actinomycetemcomitans (A. a.), Bacteroides gingivalis, B. intermedius and Wolinella recta were compared to Salmonella typhimurium LPS for their capacity to stimulate prostaglandin E2 (PGE2) release from human monocytes. Counterflow isolated monocytes were cultured with control medium or media containing 10 micrograms/ml LPS. Media were then exchanged every 24 hours for a total of 72 hours. Salmonella and Wolinella LPS preparations demonstrated seven-fold greater PGE2 release than B. gingivalis and two-fold greater than A. a. and B. intermedius. PGE2 release was found to decrease over time with all LPS preparations except Wolinella. The potency of the LPS preparations is tentatively ranked as follows: Wolinella greater than or equal to Salmonella greater than A. a. greater than B. intermedius greater than or equal to B. gingivalis. These findings demonstrate that LPS preparations from suspected periodontal pathogens are capable of stimulating PGE2 release from human monocytes. The high potency and prolonged stimulation of PGE2 release with Wolinella LPS suggests unusual toxic properties that may exert a greater influence in the pathogenesis of destructive periodontal diseases.

Actinobacillus↗

PubMed2002

[Expression of lipopolysaccharide binding protein and lipopolysaccharide receptor CD14 in experimental alcoholic liver disease].

OBJECTIVE: To observe the expression of lipopolysaccharide binding protein (LBP) and CD14 mRNA in alcohol-induced liver disease (ALD) and evaluate the relationship between the expression of LBP and CD14 mRNA and the severity of liver injury in alcoholic-fed rats. METHODS: Twenty Wistar rats were divided into two groups: ethanol-fed group and control group. Ethanol-fed group were fed ethanol (by intragastric infusion of 500 ml/L ethanol orally, dose of 5~12 g/kg/d) and control group received dextrose instead of ethanol. Rats of both groups were sacrificed at 4 weeks and 8 weeks, respectively. Levels of endotoxin and alanine transaminase (ALT) in blood were measured, and liver pathology was observed by light and electronic microscopy. Expression of LBP and CD14 mRNA in liver tissues were determined with the reverse transcription polymerase chain reaction (RT-PCR) analysis. RESULTS: Plasma endotoxin levels were increased significantly in ethanol-fed rats [(129 21) pg/ml and (187 35) pg/ml at 4 weeks and 8 weeks] than in control rats [(48 9) pg/ml and (53 11) pg/ml, respectively, t=11.2, 11.6, P<0.05]. Mean values for plasma ALT levels were increased dramatically in ethanol-fed rats after 4 weeks and 8 weeks [(112 15) U/L and (147 22) U/L, respectively] than in the control animals [(31 12)U/L and (33 9)U/L, respectively, t=5.9, 20.6, P<0.05]. In liver sections from ethanol-fed rats, there was marked pathological changes (steatosis, cell infiltration and necrosis). In the control rats, there was no significant difference in the levels of LBP and CD14 mRNA at the two time points. In ethanol-fed rats, ethanol administration led to a significant increase in LBP and CD14 mRNA levels as compared with the control group (P<0.05). CONCLUSIONS: Ethanol administration lead to a significant increase in endotoxin levels of the serum and LBP and CD14 mRNA expression in liver tissues in ethanol- fed rats when compared with the control rats. Increase of LBP and CD14 mRNA expression may result in greater sensitivity to endotoxin and thus lead to liver injury.

Alanine Transaminase↗

PubMedDate not supplied

[Binding of lipopolysaccharide and complexes of lipopolysaccharide with serum low density lipoproteins to liver macrophages].

Binding of [3H]-lipopolysaccharide toxin (LPS) and complexes of LPS with serum [125I]-labeled low density lipoproteins (LDL) with primary culture of rat liver macrophages (Kupffer cells) has been studied. Total, specific and nonspecific binding was determined. The receptor interaction was shown to dominate for both LPS and LDL-LPS complexes, amounting to 70-77% and 80-85%, respectively. The Scatchard plot was essentially non-linear for LPS binding but linear for LDL-LPS complexes. At the LPS Scatchard graph, however, two regions approximately fitting linear regression could be identified. Those regions correspond to two different types of specific binding sites: the first is for lower toxin concentrations of 0.25-0.50 microg/ml with K(d) = 0.75 microg/ml; while the second is for higher LPS concentrations of 7.5-15 microg/ml with K(d) = 5.39 microg/ml. For LDL-LPS complexes only K(d) equal to 2.80 microg/ml was ascertained. The LDL-LPS complexes significantly blocked the LPS binding (-40%) while acetylated or oxidized LDLs exerted a less pronounced effect. LPS inhibited binding of LDL-LPS complexes (-60%), while acetylated or oxidized LDLs suppressed interaction of LDL-LPS complexes with Kupffer cells insignificantly. It is suggested that, while binding to the Kupffer cell surface, a substantial portion of both LPS and LDL-LPS complexes share the same scavenger receptors with which however, modified LDLs interact weakly. The LDL-LPS complexes can interact, apart from receptors common with LPS, with other receptors exhibiting similar binding parameters, with the apo-B/E receptors playing an inessential role.

Animals↗

PubMed1990

Antigenic epitope in Pseudomonas aeruginosa lipopolysaccharide immunologically cross-reactive with Escherichia coli O26 lipopolysaccharide.

The human monoclonal antibody MH-4H7 recognizes the lipopolysaccharide outer core region of some Pseudomonas aeruginosa strains and in of some Pseudomonas aeruginosa strains and in particular strongly binds to strains of Lányi serotype 04. In this paper, we report that this monoclonal antibody also reacts with Escherichia coli O26 LPS. However, our results suggest that the previous reported immunological cross reaction between P. aeruginosa 04 and E. coli O26 strains (which was observed by using antisera against heat-stable antigens) is not due to the similarity of the O-polysaccharides.

Antibodies, Monoclonal↗

PubMed1991

Plasma lipopolysaccharide-deacylating activity (acyloxyacyl hydrolase) increases after lipopolysaccharide administration to rabbits.

Acyloxyacyl hydrolase (AOAH) is a leukocyte enzyme that removes secondary (acyloxyacyl-linked) acyl chains from the lipid A moiety of bacterial lipopolysaccharides (LPS). We now report that the same enzymatic activity is present in normal rabbit plasma and that its activity can be greatly increased by LPS challenge. Intravenous administration of LPS to rabbits resulted in a rapid increase (peaking at 90 minutes, with a mean peak increase of 16-fold) of plasma AOAH activity; the activity then slowly decreased to baseline levels over 24 hours. The plasma AOAH is probably derived, at least in part, from circulating leukocytes, since (a) the AOAH response was significantly diminished in leukopenic rabbits, and (b) incubation of blood or isolated leukocytes with LPS in vitro resulted in increased extracellular AOAH activity. These results indicate that AOAH can appear extracellularly, in plasma, as part of the early response to intravenous LPS challenge. The cellular source(s) and biological role of the plasma enzyme remain to be determined.

Animals↗

PubMed1989

[Structure of the O-specific polysaccharide of the Yersinia enterocolitica serovar O:4.32 lipopolysaccharide. Serologic relations of lipopolysaccharides of Y. enterocolitica O:4.32 and Y. intermedia O:4.33].

O-Specific polysaccharide has been isolated on mild acid hydrolysis of the lipopolysaccharide from Yersinia enterocolitica O: 4.32 (strain 96) and shown to consist of yersiniose B (3,6-dideoxy-4-C-(1-hydroxyethyl)-D-xylo-hexose, YerB) acetylated at C1' and 2-acetamido-2-deoxy-D-galactose residues in a molar ratio 1:2. Acid hydrolysis, methylation and 13C NMR studies indicated the polysaccharide to be composed of trisaccharide repeating units of the following structure: (sequence; see text) The data obtained revealed structural and serological interrelation between O-antigens of Y. enterocolitica O:4.32 and Y. intermedia O:4.33.

Antigens, Bacterial↗

PubMed1989

Lipopolysaccharide interaction with lysozyme. Binding of lipopolysaccharide to lysozyme and inhibition of lysozyme enzymatic activity.

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.

Affinity Labels↗

PubMed1977

Immunologic properties of protein-lipopolysaccharide complexes. I. Antibody response of normal, thymectomized, and nude mice to a lysozyme-lipopolysaccharide complex.

The in vivo antibody response to the lysozyme component of a lysozyme-lipopolysaccharide complex has been investigated in normal, thymectomized and nude mice. The splenic PFC response elicited by the complex in CBA mice is 10- to 20-fold higher than the response elicited by lysozyme admixed with LPS. Both lysozyme-LPS complexes and lysozyme + LPS mixtures prime mice for a subsequent secondary anti-lysozyme response. In contrast, thymectomized mice responded poorly to lysozyme-LPS complexes unless reconstituted with splenic T cells. However, nude mice responded as well as Nu/+ controls to the complex. The PFC response of normal and of nude mice was severely depressed by treatment with anti-lymphocyte serum. These findings suggest that T lymphocytes contribute significantly to the enhanced immune responsiveness associated with LPS administration.

Animals↗

PubMed1979

Synergy between T cell-replacing factor and bacterial lipopolysaccharides (LPS) in the primary antibody response in vitro: a model for lipopolysaccharide adjuvant action.

Unfractionated spleen cells, B cells from normal mice, and nu/nu spleen cells respond to the addition of bacterial lipopolysaccharide (LPS) and T-cell-replacing factor (TRF) by production of plaque-forming cells (PFC) in excess of the number expected from the addition of LPS and TRF separately. This synergistic activity is dependent on the presence of the antigen, SRBC. Supernatants of both allogeneic spleen cell mixtures and spleen cells cultured with Con A are effective and synergize best at concentrations suboptimal for their ability to act as TRF alone. Culture supernatants of unstimulated normal or fractionated cell populations are ineffective. Synergy is not dependent on the presence of macrophages in the cultures. Purified LPS free from active contaminants, as well as commercially available LPS, show synergy with TRF. Synergy was seen when TRF was added at initiation of culture or 24 hr later. It is suggested that synergy is the equivalent of LPS adjuvant activity, that the role of T cells in LPS adjuvanticity is that of a conventional cooperating cell, and the LPS acts as an adjuvant by inducing B cells to become more sensitive to T cell helper factors.

Adjuvants, Immunologic↗

PubMed1979

Mechanisms of lipopolysaccharide-initiated rabbit platelet responses. II. Evidence that lipid A is responsible for binding of lipopolysaccharide to the platelet.

The mechanism of bacterial lipopolysaccharide-(LPS) initiated, complement-(C) mediated rabbit platelet lysis has been examined. The results of these studies support our previous observations that activation of the alternative C pathway is required for platelet lysis and that preparations of LPS that activate only the classical pathway (e.g., lipid A) do not cause lysis. The temporal relationship of the interaction of the LPS with the platelet before the addition of plasma suggests a time-dependent association of the LPS with the platelet. On the basis of a number of experiments, including inhibition with polymyxin B, treatment of LPS with alkali, and blocking experiments with polysaccharide-free LPS preparations, it is concluded that the lipid A region of the LPS molecule is responsible for attaching the LPS to the platelet. Finally, a comparison of the activity of lipid A-associated protein-LPS complexes with protein-free LPS demonstrated that an equivalent extent of platelet lysis was achieved with one-one hundredth the concentration of the former as that required for protein-free LPS. The data suggest that LAP facilitates attachment of the LPS to the platelet.

Animals↗

PubMed1982

Lipopolysaccharides from Pseudomonas maltophilia. Structural studies of the side-chain, core, and lipid-A regions of the lipopolysaccharide from strain NCTC 10257.

Structural studies have been carried out on the O-specific polysaccharide, the core oligosaccharide, and the lipid A from the lipopolysaccharide of Pseudomonas maltophilia NCTC 10257. By means of 13C nuclear magnetic resonance spectroscopy, a tetrasaccharide repeating-unit for the O-specific polymer has been confirmed. However, the data suggest that the L-rhamnopyranosyl residue at the branching point has the alpha configuration rather than beta as proposed previously [Neal, D.J. and Wilkinson, S.G. (1979) Carbohydr. Res. 69, 191-201]. The core oligosaccharide contains residues of D-glucose, D-mannose phosphate, D-galactosamine (not N-acetylated), D-galacturonic acid, and a 3-deoxyoctulosonic acid (but no aldoheptose). A partial structure for the oligosaccharide is proposed. Lipid A is based on phosphorylated glucosamine residues, with N-fatty acyl and O-fatty acyl substituents. The major fatty acids are 9-methyldecanoic acid, 2-hydroxy-9-methyldecanoic acid, 3-hydroxy-9-methyldecanoic acid (each ester-linked), 3-hydroxydodecanoic acid, and 3-hydroxy-11-methyldodecanoic acid (both mainly amide-linked). The results of this study provide further evidence for a relationship between P. maltophilia and some Xanthomonas species.

Chemical Phenomena↗

PubMed1995

L-rhamnose inhibits proliferation of murine splenocytes by the lipopolysaccharide and polysaccharide moiety of Shigella dysenteriae type 1 lipopolysaccharide.

The induction of proliferation of murine splenocytes by lipopolysaccharide (LPS) of Shigella dysenteriae type 1 and its polysaccharide (PS) and lipid A fractions was investigated. The LPS-induced proliferation reached a maximum at a concentration of 30 ng/ml. The PS and lipid A induced proliferation of murine splenocytes at similar concentrations. Preincubation of murine splenocytes with varying concentrations of L-rhamnose blocked LPS- and PS-induced proliferation in a dose-dependent manner. The lipid A-induced stimulation, on the contrary, was not affected by preincubation of the cells with L-rhamnose. These data suggest that activation of splenocytes by LPS and PS is mechanistically different from that induced by lipid A and is presumably involved in the specific recognition of carbohydrate structures on LPS and PS.

Animals↗