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PubMed1995

Immunization of dairy cows with an Escherichia coli J5 lipopolysaccharide vaccine.

Development of a lipopolysaccharide-protein conjugate vaccine and the immunological response to the vaccine were investigated. Lipopolysaccharide derived from Escherichia coli J5 was detoxified by mild alkaline hydrolysis. Detoxification reduced endotoxin activity 2500-fold compared with that of native J5 lipopolysaccharide. The conjugate vaccine was synthesized by covalently coupling detoxified lipopolysaccharide to chicken serum albumin by reductive amination. Dairy cows were immunized with 8.35 mg of conjugate (n = 3) or 5 x 10(9) heat-killed J5 bacterin (n = 5) at 215 DIM and received a secondary immunization 14 d later. Control cows were not immunized. Immunization enhanced serum antibody titer to J5 lipopolysaccharide antigens. Whey IgG and IgM titers to J5 lipopolysaccharide were not different among treatment groups. Serum and whey IgG titers to J5 whole-cell antigens were elevated in immunized cows within treatment groups. Immunization did not enhance whey IgM to J5 whole-cell antigens. Conjugate immunization elicited an immune response comparable with or greater than that of immunized cows with J5 bacterin.

Animals↗

PubMed1999

Effect of ebrotidine on gastric mucosal inflammatory responses to Helicobacter pylori lipopolysaccharide.

UNLABELLED: Helicobacter pylori lipopolysaccharide is a primary virulence factor responsible for eliciting acute mucosal inflammatory responses associated with H. pylori infection. In this study, we applied the animal model of H. pylori lipopolysaccharide-induced acute gastritis to assess the effect of antiulcer agent, ebrotidine, on the gastric mucosal inflammatory responses by analyzing the interplay between the activity of a key apoptotic caspase, caspase-3, epithelial cell apoptosis, and the expression of inducible nitric oxide synthase (NOS-2). METHODS: Rats, pretreated twice daily with ebrotidine at 100 mg/kg, or the vehicle, were subjected to intragastric application of H. pylori lipopolysaccharide at 50 microg/animal, and after 4 additional days on the antiulcer drug or vehicle regimen their mucosal tissue used for histologic assessment, assays of epithelial cells apoptosis, and the measurements of caspase-3 and NOS-2 activities. RESULTS: In the absence of antiulcer agent, H. pylori lipopolysaccharide induced acute reaction characterized by the inflammatory infiltration of the lamina propria, hyperemia, and epithelial hemorrhage. This was accompanied by an 11.2-fold increase in epithelial cell apoptosis, a 6.5-fold induction in mucosal expression of NOS-2, and a 5.4-fold increase in caspase-3 activity. Treatment with H2-receptor antagonist ebrotidine, also known for its gastroprotective effects, produced a 50.9% reduction in the extent of mucosal inflammatory changes elicited by H. pylori lipopolysaccharide and an 82.5% decrease in the epithelial cells apoptosis, while the activity of caspase-3 decreased by 33.7% and that of NOS-2 showed a 72.8% decline. CONCLUSIONS: The findings implicate caspase-3 involvement in gastric mucosal inflammatory responses to H. pylori lipopolysaccharide, and point towards participation of NOS-2 in the amplification of the cell death-signaling cascade. Our study also demonstrate that ebrotidine exerts modulatory effect on the H. pylori-induced mucosal inflammatory responses by interfering with the events propagated by NOS-2 and caspase-3.

Acute Disease↗

PubMed1992

Selective expression of mitogen-inducible cyclooxygenase in macrophages stimulated with lipopolysaccharide.

Two forms of cyclooxygenase are known to be present in eukaryotic organisms: a cyclooxygenase (COX-1) first purified from ram seminal vesicles encoded by a 2.8-kilobase mRNA, and a newly discovered mitogen-inducible cyclooxygenase (COX-2) encoded by a 4-kilobase mRNA. Expression of these two forms of the enzyme in rat alveolar macrophages stimulated with lipopolysaccharide was investigated by 1) determining the activity of newly synthesized enzyme after inactivating the endogenous enzyme with aspirin; 2) comparing levels of newly synthesized enzyme proteins in cells treated with or without lipopolysaccharide; and 3) assessing the expression of the mRNAs encoding COX-1 and COX-2. Levels of enzyme proteins were assessed by Western blot analysis and immunoprecipitation of 35S-labeled enzyme using two different antibodies, one specific for COX-2 and the other recognizing both forms of the enzyme but preferentially recognizing COX-1. We report here that the enhanced cyclooxygenase activity induced by the bacterial lipopolysaccharide in rat alveolar macrophages is caused by selective expression of the COX-2. Expression of COX-2 in macrophages stimulated by lipopolysaccharide was completely inhibited by dexamethasone, whereas COX-1 was unaffected. In resting unstimulated macrophages, only COX-1 but not COX-2 was detected. Levels of mRNA for the COX-2 in macrophages were increased, but those of the COX-1 were not affected by lipopolysaccharide as assessed by reverse transcription coupled with polymerase chain reaction. These results indicate that increased synthesis of prostaglandins and thromboxanes in lipopolysaccharide-stimulated macrophages results from selective expression of COX-2.

Animals↗

PubMed1977

Effect of variations in lipopolysaccharide on the fluidity of the outer membrane of Escherichia coli.

The lipid hydrocarbon chains in the outer membrane of gram-negative bacteria appear from previous experiments to be less mobile than in the cytoplasmic membrane. To determine whether lipopolysaccharide, a unique outer membrane component, is a cause of this restricted mobility, outer membranes differing in the amount of lipopolysaccharide, and the length of the polysaccharide side chain, were prepared from Escherichia coli J5. Cytoplasmic membranes were prepared for comparison. The probes, 5- and 12-doxylstearate, were introduced into these membranes, electron spin resonance spectra were analyzed, and the order parameter (S) and empirical motion parameter (tau0) were calculated. Outer membrane preparations containing long chain lipopolysaccharide were much less fluid by these criteria than were preparations containing short chain lipopolysaccharide. Removing about 40% of the lipopolysaccharide from the former preparations greatly increased their fluidity. The lipid in the cytoplasmic membrane preparations was more fluid than in the outer membrane and cytoplasmic membranes were similar to each other regardless of the composition of the outer membrane. These results indicate that lipopolysaccharide, and especially the polysaccharide portion, directly or indirectly causes the restricted mobility of the lipid hydrocarbon chains observed in the outer membrane.

Cell Membrane↗

PubMed1985

Selective glomerular thrombosis in rats induced by combined injections of nephrotoxic antiserum and lipopolysaccharide.

Experimental glomerular thrombosis was induced in rats by combined injections of nephrotoxic antiserum and lipopolysaccharide. For the development of glomerular thrombosis, administration of nephrotoxic antiserum (greater than or equal to 0.1 ml pooled material) was required as a preparatory agent and greater than or equal to 100 ng lipopolysaccharide as a provoking agent. The severity of renal lesions was not parallel with the amounts of nephrotoxic antiserum and lipopolysaccharide injected. Transient clamping of a unilateral renal artery for 10 to 20 minutes at the time of the nephrotoxic antiserum injection partially prevented the development of glomerular thrombosis in the clamped side. Intervals between the preparatory and provoking injections were found to be -4 to 72 hours for the development of renal lesions. With the preparatory injection of 0.1 to 0.3 ml nephrotoxic antiserum a thrombotic lesion developed exclusively in glomerular capillary walls greater than or equal to 2 hours after the lipopolysaccharide injection. No thrombotic lesion was observed in other tissues such as lung, liver, or intestine, but a generalized Shwartz-manlike phenomenon was observed with the preparatory injection of 0.5 ml nephrotoxic antiserum. When rats were pretreated with nephrotoxic antiserum and 3 hours thereafter transfused with 1 to 3 X 10(8) polymorphonuclear leukocytes, which had been incubated with lipopolysaccharide for 30 minutes in vitro and washed three times with buffered physiologic saline solution, a marked glomerular thrombosis was also induced. The result indicates that lipopolysaccharide plays a role in the development of thrombosis by a direct effect on leukocytes. The development of glomerular thrombosis was prevented in a leukocytopenic state when leukocyte count was less than 600/microliter, but not in thrombocytopenic rats with a platelet count 8.7 to 30 X 10(3)/microliter. Leukocyte count and plasma fibrinogen level decreased, and prothrombin time and activated partial thromboplastin time were prolonged significantly during the pathologic course. Platelet count and FDP did not change significantly. This experimental model has a basic similarity to the generalized Shwartzman reaction, but the lesions develop exclusively in glomeruli.

Animals↗

PubMed1994

Lipopolysaccharide induces monocyte chemoattractant protein production by rat mesangial cells.

Lipopolysaccharide, a potent pro-inflammatory constituent of bacterial cell walls, is capable of promoting glomerular inflammation, by both activating circulating inflammatory cells and local interactions with renal parenchymal cells. We sought to determine whether lipopolysaccharide was capable of promoting glomerular inflammation by directly stimulating mesangial cell production of monocyte chemoattractant protein 1, a recently described cytokine capable of eliciting recruitment of mononuclear phagocytes into inflammatory foci. Northern hybridization analysis revealed dose and time-dependent induction of mRNA coding for monocyte chemoattractant protein 1 in quiescent rat mesangial cells treated with lipopolysaccharide. Lipopolysaccharide-elicited induction of monocyte chemoattractant protein mRNA was detectable after 1 hour and persisted for at least 30 hours. Media isolated from rat mesangial cell cultures stimulated by lipopolysaccharide possessed monocyte chemotactic activity that was detectable at 8 hours and peaked at 24 hours; an antimonocyte chemoattractant protein antibody blocked 87% of this chemotactic activity. We suggest that lipopolysaccharide, released from bacterial cell walls, promotes glomerular inflammation by stimulating mesangial cell production of monocyte chemoattractant protein 1.

Animals↗

PubMed1994

Activation of hepatic proliferation-associated transcription factors by lipopolysaccharide.

BACKGROUND: The hepatic acute-phase response is the result of reprogramming of gene expression in the liver. Similar acute-phase responses occur in regenerating liver after partial hepatectomy and are preceded by increases in the expression of a set of transcriptional regulatory proteins that are encoded by "immediate-early" genes. The purpose of this study was to determine whether acute systemic inflammation after lipopolysaccharide injection induces hepatic immediate-early genes that are induced by partial hepatectomy. METHODS: Two- to 4-month-old Balb/c mice received intraperitoneal Escherichia coli lipopolysaccharide (0111:B4; 100 micrograms), and total liver RNA, nuclear protein extracts, or total liver protein lysates were obtained at 0, 1, 3, 12, and 24 hours. RNA blot hybridization analysis was used to determine steady-state messenger RNA levels for c-jun, jun-B, jun-D, c-fos, fos-B, fra-1, nup475, and zif268. Specific nuclear protein-binding activity was determined by gel mobility shift assay. The protein c-Jun was detected by antibody-blocking experiments, and Jun-B was detected by gel supershift assay of the activating protein (AP-1) complex. Steady-state Jun-B levels were determined by immunoblot analysis. RESULTS: Intraperitoneal injection of lipopolysaccharide is followed by induction (from fivefold to 13-fold) of c-jun, jun-B, c-fos, zif268, and nup475 messenger RNAs in the liver. Lipopolysaccharide induced increases in AP-1 and Zif268 consensus DNA-binding activity in mouse liver. The proteins c-Jun and Jun-B are detected in the AP-1 complex after administration of lipopolysaccharide. CONCLUSIONS: The induction of hepatic immediate-early genes after lipopolysaccharide is similar to that that follows partial hepatectomy. These transcription factors likely have important roles in the reprogramming of gene expression that leads to the acute-phase response.

Animals↗

PubMed1993

Inhibition of lipopolysaccharide-induced macrophage tumor necrosis factor-alpha synthesis by polymyxin B sulfate.

The antibiotic polymyxin B sulfate is a cationic polypeptide with a unique cyclical configuration and distinct cationic characteristics. In this investigation, polymyxin B was evaluated to determine its ability to prevent synthesis of lactic acid and tumor necrosis factor-alpha (TNF-alpha) by lipopolysaccharide-stimulated strain RAW 264.7 macrophage-like cell populations. In this context, gradient concentrations of polymyxin B were formulated in the presence of fixed concentrations of lipopolysaccharide fractions from Escherichia coli (B4:0111), E coli (J5), Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella minnesota, and S typhimurium (Re). Quantitation of TNF-alpha was established by the application of a tissue culture-based biological assay system, using the WEHI 164 clone 13 indicator cell line. Investigations also included evaluation of the ability of gradient concentrations of lipopolysaccharide fractions from E coli (B4:0111), E coli (J5), K pneumoniae, P aeruginosa, S minnesota, and S typhimurium (Re) to form a complex with polymyxin B. This was established through application of high-performance thin-layer chromatography techniques. On the basis of the known molecular characteristics of lipopolysaccharide, its lipid A-core subfractions, and polymyxin B, these results imply that cytoprotective properties of polymyxin B are attributable to direct interaction and subsequent complex formation. More specifically, the mechanism by which polymyxin B exerts affinity for lipopolysaccharide fractions is proposed to occur through attractive ionic interactions established between the cationic diaminobutyric acid residues of polymyxin B and the mono- or diphosphate group(s) of the lipid A-core moiety. It is highly probable that this molecular phenomenon is accompanied by hydrophobic interactions established between the terminal methyloctanoyl or methylheptanoyl groups of polymyxin B and the saturated carbon chains of the lipid A-core subfraction of lipopolysaccharide fractions.

Animals↗

PubMedDate not supplied

Hepatoprotective effect of SY-640, a novel acetamide derivative, on Propionibacterium acnes and lipopolysaccharide-induced liver injury in mice.

The hepatoprotective effect of SY-640 on Propionibacterium acnes and lipopolysaccharide-induced liver injury in mice and its protective mechanism were examined. Oral administration of SY-640, 150 mg/kg once daily for 7 days, significantly inhibited Propionibacterium acnes and lipopolysaccharide-induced liver injury, but a single administration was without effect. Liver-infiltrating cells (T-lymphocytes and macrophages) play an important role in Propionibacterium and lipopolysaccharide-induced liver injury and express a higher level of leukocyte function-associated antigen-1. SY-640 inhibited the number of liver-infiltrating cells and attenuated the increased expression of leukocyte function-associated antigen-1 on these cells. Tumor necrosis factor-alpha mediated Propionibacterium acnes and lipopolysaccharide-induced liver injury, and SY-640 inhibited the elevation of the serum tumor necrosis factor-alpha concentration after injection of lipopolysaccharide in Propionibacterium acnes-primed mice. The putative effects of SY-640 are inhibitory effects on infiltration into the liver and on activation of T-lymphocytes and macrophages after Propionibacterium acnes-priming, and attenuation of expression of cell adhesion molecules such as leukocyte function-associated antigen-1. The immunological effect of SY-640 is likely to be closely related to the inhibition of Propionibacterium and lipopolysaccharide-induced liver injury.

Acetamides↗

PubMed1998

Lipopolysaccharide a virulence factor of Helicobacter pylori: effect of antiulcer agents.

Helicobacter pylori plays a major role in the pathogenesis of gastric disease. The gastric epithelial integrity is compromised by the H. pylori cell wall lipopolysaccharide untoward effect on the gastric epithelial cell receptors interaction with proteins of extracellular matrix, glycoproteins of mucus coat, and bioactive peptides. These interactions cause the weakening of the mucus coat rendering the underying epithelium vulnerable to noxious luminal contents and disrupting the regulatory feedback of somatostatin and gastrin. Moreover, H. pylori lipopolysaccharide induces histologic lesions typical of acute gastritis and these changes are reflected in the increased epithelial cell apoptosis. These findings thus identify cell wall lipopolysaccharide as a virulent factor responsible for the H. pylori effect on gastric epithelium. The effect of antiulcer agents on the interference of lipopolysaccharide with the laminin receptor was found to be most efficiently countered by ebrotidine, sulglycotide and sucralfate, whereas sulglycotide is the most potent in the reversal of the inhibitory effect of the lipopolysaccharide on mucin receptor binding. In the case of somatostatin-receptor binding, sulglycotide followed by sucralfate and ebrotidine showed the most potency in of reversing the effect of H. pylori lipopolysaccharide. Thus these antiulcer agents have a great promise in the treatment gastric diseases associated with H. pylori infection.

Anti-Ulcer Agents↗

PubMed1998

[Isolation and chemical characterization of type R lipopolysaccharides of a hypovirulent strain of Yersinia pestis].

The lipopolysaccharides LPS I and LPS II, isolated from the hypovirulent EV40 strain of Yersinia pestis, are composed only of type R lipopolysaccharides. This type consists of two forms a and b, depending on their solubility pattern in a solvent mixture containing varying proportions of chloroform, methanol, hexane, and hydrochloric acid. LPS I consists of one subtype, RIb, while LPS II consists of two subtypes, RIIa and RIIb. Analysis by gel electrophoresis shows that the mass of these lipopolysaccharide forms are in the vicinity of 2000-3000 Da. The RIb and RIIb subtypes, which are found in the majority of lipopolysaccharide I and II fractions, are composed of ketoses and amines that are similar to those occurring in LPS I and LPS II. In contrast, the two subtypes RIIa and RIIb are different both in terms of the composition of lipid A and the extent of its substitution. Certain fractions of RIIa contain only lipid A and 3-deoxy-D-manno-octulosonic acid (KDO), while other fractions of RIIb possess a lipid A, which is not substituted by arabinose. The whole set of these R-type lipopolysaccharide forms are excellent models for the study of the role of the primary structure of the polysaccharide region, and for the effect of lipid A substitution on the biological activity of bacterial lipopolysaccharides.

Electrophoresis, Polyacrylamide Gel↗

PubMed1997

Influence of pentoxifylline on fevers induced by bacterial lipopolysaccharide and tumor necrosis factor-alpha in guinea pigs.

In guinea pigs intraperitoneal (i.p.) injections of 50 mg/kg pentoxifylline had no influence on abdominal temperature while higher doses of pentoxifylline caused a hypothermic response lasting for 2-3 h. Administration of 50 mg/kg pentoxifylline 1 h before intramuscular (i.m.) injections of 20 micrograms/kg bacterial lipopolysaccharide reduced the lipopolysaccharide-induced production of endogenous tumor necrosis factor-alpha (TNF-alpha) by 68%. The second phase of lipopolysaccharide-induced fever was significantly attenuated by pretreatment with 50 mg/kg pentoxifylline, a dose which had, per se, no influence on core temperature of guinea pigs. The thermal response of guinea pigs to administration of exogenous TNF-alpha was not modulated by pretreatment with pentoxifylline. Intra-arterial infusions with 5 micrograms/kg TNF-alpha, a dose which yielded the same circulating TNF bioactivity as i.m. injections of 20 micrograms/kg lipopolysaccharide, induced a biphasic febrile response. The magnitude and duration of TNF-induced fever were the same whether guinea pigs were pretreated with pentoxifylline or with 0.9% saline. The results indicate that endogenous formation of TNF-alpha may contribute to the development of fever induced by lipopolysaccharide, but is not its only mediator, since the first phase of lipopolysaccharide-induced fever was not altered by the blockade of TNF production.

Analgesics, Non-Narcotic↗

PubMed1978

Host-Symbiont Interactions: III. Purification and Partial Characterization of Rhizobium Lipopolysaccharides.

The lipopolysaccharides of three strains each of Rhizobium leguminosarum, R. phaseoli, and trifolii have been purified and partially characterized. The last step in the purification procedure is gel filtration column chromatography using Sepharose 4B with an elution buffer consisting of ethylenediaminetetraacetic acid and triethylamine. Each of the lipopolysaccharides reported in this paper elutes as a symmetrical peak in the partially included volume of this Sepharose 4B column. The ratio of 2-keto-3-deoxyoctonate acid (a sugar which is characteristic of lipopolysaccharides) to hexose is constant throughout the carbohydrate-containing peaks as they elute from the Sepharose 4B. The compositions and immunodominant structures of the purified lipopolysaccharides vary as much among strains of a single Rhizobium species as among the different species of Rhizobium. There is no obvious correlation between the nodulation group to which a Rhizobium belongs and the chemical composition or immunochemistry of the Rhizobium's lipopolysaccharide. There is extensive crosslysis by phage of strains of R. trifolii, R. phaseoli, and R. leguminosarum. This suggests that the receptors for these cross-lysing phage reside either in nonlipopolysaccharide structures or in common structures within the lipopolysaccharide which are not detected by compositional or immunochemical analysis.

Journal Article↗

PubMed1997

Structural characterization of lipid A obtained from Pantoea agglomerans lipopolysaccharide.

Lipopolysaccharide isolated from Pantoea agglomerans showed higher priming and triggering activities for macrophages in terms of tumor necrosis factor production than other lipopolysaccharides. To identify the difference in biological activities of lipopolysaccharide of Pantoea agglomerans from other lipopolysaccharides on the basis of structure, we determined the structure of the lipid A part, which is the biological center of lipopolysaccharides, by quantitative analysis, nuclear magnetic resonance spectroscopy and mass spectrometry. Lipopolysaccharide of Pantoea agglomerans is constructed with at least two kinds of lipid A of different levels of acylation. One is of the same type as that of Escherichia coli with hexa-acyl lipid A and the other is the Salmonella minnesota type with hepta-acyl lipid A.

Bacterial Proteins↗

PubMed1971

Attachment of flagellar basal bodies to the cell envelope: specific attachment to the outer, lipopolysaccharide membrane and the cyoplasmic membrane.

A procedure is described for the purification of the Escherichia coli outer membrane (lipopolysaccharide or L membrane) with flagella still attached. The resulting lipopolysaccharide membrane was in the form of vesicles that had a trilaminar structure in thin section and contained about 55% lipopolysaccharide and 45% protein. T2 or T4 phage preadsorbed to E. coli were found attached to the purified lipopolysaccharide membrane. Flagella were bound to the purified lipopolysaccharide membrane specifically at the basal body ring closest to the hook (the L ring). The cytoplasmic membrane in preparations from osmotically lysed E. coli spheroplasts or Bacillus subtilis protoplasts was specifically attached to flagella at the basal body ring farthest from the hook (the M ring). In the E. coli preparation, lipopolysaccharide membrane was also present and was attached to the L ring. From these data and a knowledge of the structure and dimensions of the E. coli flagellar basal body and cell envelope, a model for flagellar attachment is deduced.

Adenosine Triphosphatases↗

PubMed2004

Tetrahydrobiopterin biosynthesis in white and brown adipose tissues is enhanced following intraperitoneal administration of bacterial lipopolysaccharide.

Tetrahydrobiopterin is an essential cofactor for nitric oxide synthase (NOS). This study was undertaken to examine the effects of intraperitoneally injected lipopolysaccharide on tetrahydrobiopterin biosynthesis in murine white and brown adipose tissues. Tetrahydrobiopterin content, catalytic activity and mRNA expression level of GTP cyclohydrolase I (GCH), rate-controlling enzyme in de novo biosynthesis of tetrahydrobiopterin, in both adipose tissues were up-regulated by 500-microg lipopolysaccharide at 6 h after the injection. On the contrary, treatment of 3T3-L1 adipocytes with lipopolysaccharide alone did not affect GCH mRNA expression level, whereas the combination of lipopolysaccharide, tumor necrosis factor (TNF)-alpha, and interferon gamma induced the increase in expression levels of GCH mRNA and CD14 mRNA. Collectively, our results showed that tetrahydrobiopterin biosynthesis can be augmented by increased GCH activity caused by a synergistic effect of lipopolysaccharide and cytokines in white and brown adipose tissues. These observations support the view that tetrahydrobiopterin biosynthesis in the adipose tissues is a target of inflammatory events triggered by peripheral LPS injection.

3T3-L1 Cells↗

PubMed2005

Lipopolysaccharide mediated regulation of neuroendocrine associated proprotein convertases and neuropeptide precursor processing in the rat spleen.

Within the secretory pathway, the family of proprotein convertases cleave inactive precursors at paired basic residues to generate a myriad of biologically active peptides. Within the PC family, PC1/3 and PC2 are well known for their preferential expression within neuroendocrine cells. However, various data now indicate their potential expression in immune cells. The aim of our study was two fold: (1) survey PC expression in immune tissues, with emphasis on PC1/3 and PC2 and (2) examine PC expression under conditions that mimic an infectious state using lipopolysaccharide, known to activate immune cells via toll-like receptors. Spatial and temporal analyses of tissues from control and lipopolysaccharide treated rats were carried out using in situ hybridization histochemistry, Northern blot, mass spectrometry and antibacterial assays. Our tissue survey showed the basal expression of all PCs in the lymph nodes, thymus and spleen including PC1/3 and PC2. Focusing on the spleen, basal expression of PC1/3 was seen in the red pulp/marginal zone areas, suggesting expression within macrophages. Lipopolysaccharide treatment produced significant changes in PC1/3 expression and notably an induction in B lymphocytes within germinal centers. Similarly, PC2, which was undetectable in control spleens, was induced in germinal centers following lipopolysaccharide treatment. The PC1/3 and PC2 substrate proenkephalin was also induced following lipopolysaccharide treatment in the marginal zone, where PC1/3 expression was also found. Mass spectrometry analysis of spleen extracts demonstrated the presence of the antibacterial peptide enkelytin. Our studies confirmed that PC1/3 and PC2 expression was not restricted to neurons and endocrine cells, but was also found under basal conditions in both macrophage and lymphocytes. Additionally, plasticity of PC expression in immune cells was observed under conditions that mimic pathogen-like infections, suggesting a mechanistic link through Toll-like receptors. Collectively, these data clearly implicate PCs in immune responses, both innate and acquired.

Animals↗

PubMed2001

Effect of recombinant bactericidal/permeability-increasing protein on endotoxin translocation and lipopolysaccharide-binding protein/CD14 expression in rats after thermal injury.

OBJECTIVE: To investigate the potential mechanisms underlying the in vivo effect of recombinant bactericidal/permeability-increasing protein (rBPI21) on endogenous bacteria or endotoxin translocation and lipopolysaccharide-binding protein/CD14 expression secondary to thermal injury. DESIGN: Prospective, randomized, controlled animal study. SETTING: College hospital animal research laboratory. SUBJECTS: Thirty-six male Wistar rats weighing 250-300 g. INTERVENTIONS: The rats were anesthetized, and a 35% total body surface area full-thickness burn was created. Animals were randomized to receive treatment with either rBPI21 or the control protein (albumin). rBPI21 (2 mg/kg body wt, BPI group) or a protein control preparation (burn group) in the same dose was administered in an intravenous bolus at 30 mins and 4 hrs after thermal injury. All animals were killed at 12 and 24 hrs postburn (six to ten rats for each interval). In addition, eight rats were taken as normal controls. MEASUREMENT AND MAIN RESULTS: Our data showed that treatment with rBPI21 was effective in preventing endotoxin translocation secondary to severe burns. Meanwhile, tissue lipopolysaccharide-binding protein, CD14, and tumor necrosis factor-alpha mRNA expression in various organs were inhibited markedly by rBPI21 secondary to acute insults (p <.05-.01). Furthermore, significant reduction in serum aminoleucine transferase concentrations and elevation in intestinal diamine oxidase activities in the rBPI21-treated group were found compared with controls (p <.05-.01). CONCLUSIONS: These findings indicate that endotoxin accumulated in local sites after thermal injury can markedly up-regulate lipopolysaccharide-binding protein/CD14 and tumor necrosis factor-alpha mRNA expression in various organs. Meanwhile, up-regulation of lipopolysaccharide-binding protein/CD14 expression would be the major molecular mechanism of increasing sensitivity to endogenous endotoxin response after burns. Early treatment with rBPI21may be effective in attenuating multiple organ damage resulting from gut-origin endotoxin translocation. This might be associated with the down-regulation effects of tissue lipopolysaccharide-binding protein and CD14 gene expression by the use of rBPI21.

Acute-Phase Proteins↗