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)

Human brucellosis is characterized by the presence of both acute inflammatory episodes and chronic inflammation with granuloma formation. On this basis, the proinflammatory effects of smooth lipopolysaccharide of Brucella (S-LPS) were addressed and compared to those of LPS from Escherichia coli. For this purpose, the induction of cyclooxygenase-2 (COX-2), the production of the chemokine monocyte chemoattractant protein-1 (MCP-1), and the activation of the nuclear factor kappa B (NF-kappa B) were studied. S-LPS was found to induce both COX-2 expression and MCP-1 production; however, the potency of E. coli LPS exceeded that of Brucella S-LPS by some orders of magnitude. However, at concentrations above 1 microg/ml, all of the LPS produced comparable effects, including their ability to activate the NF-kappa B system. These observations help explain the inflammatory events associated with Brucella infection and the ability of Brucella to produce monocyte recruitment and granuloma formation.
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PMID:Brucella lipopolysaccharides induce cyclooxygenase-2 expression in monocytic cells. 1171 82

To test the efficacy of rough Brucella strain vaccines in sheep, a vaccine recently developed in cattle (Brucella abortus strain RB51) was assessed in comparison with the conventional Rev. 1 vaccine. Forty-five ewes from twelve to fourteen months of age, from brucellosis-free flocks, were allotted to three groups of fifteen ewes each. Group one was vaccinated by the conjunctival route with 1.73 x 10(8) colony forming units (CFU) of Rev. 1 vaccine. Group two was vaccinated subcutaneously with 11 x 10(9) CFU of RB51 vaccine and group three was considered as a control. All sheep were challenged at two to three months of gestation with 5 x 10(7) CFU of virulent B. melitensis H38. Vaccination with RB51 vaccine did not result in the production of any antibodies against the O-side chain of lipopolysaccharide, as measured by conventional serological tests (Rose Bengal plate test and complement fixation test). Protection of sheep against abortion and excretion of virulent Brucella strain in vaginal fluid, aborted foetuses and/or non viable lambs at parturition and abortion was significantly lower than that afforded by Rev. 1 vaccine. The difference compared to the control group was not significant. Data from this study suggest that the RB51 vaccine used for cattle vaccination does not provide effective protection of sheep against abortion induced by B. melitensis.
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PMID:Comparison of the efficacy of Brucella abortus strain RB51 and Brucella melitensis Rev. 1 live vaccines against experimental infection with Brucella melitensis in pregnant ewes. 1173 16

The avidin-biotin enzyme-linked immunosorbent assay (A-B ELISA), for use in surveillance for bovine brucellosis in India was developed and calibrated using the indirect brucellosis ELISA kit of the International Atomic Energy Agency (IAEA) as a reference. The reagents used in the A-B ELISA were as follows: the smooth lipopolysaccharide of Brucella abortus strain 99 (antigen); biotinylated anti-bovine immunoglobulin G (detection antibody); avidin-horseradish peroxidase (conjugate); and O-phenylenediamine dihydrochloride (chromogen). The test results were interpreted using the IAEA software EDI version 2.1.1, which was modified for use in the A-B ELISA. The cut-off percentage positivity value was established using 500 brucellosis-positive and 500 brucellosis-negative serum samples, confirmed with reference to the sample data using the indirect ELISA kit. The overall specificity of A-B ELISA was 98.8% and overall sensitivity was 98.2%. Field validation of the A-B ELISA kit was undertaken in six laboratories in India. Screening of 7,040 cattle and 678 buffalo serum samples from 12 states revealed serological evidence of brucellosis in 8.7% of cattle and 10.2% of buffalo. This kit proved to be robust and performed with a similar sensitivity and specificity to the indirect ELISA. The kit can be supplied at a lower cost than current commercial ELISA kits.
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PMID:Development and field validation of an avidin-biotin enzyme-linked immunosorbent assay kit for bovine brucellosis. 1173 17

Brucella is a facultative intracellular parasite that causes brucellosis in animals and humans. The protective immune response against Brucella involves both humoral and cell-mediated immunity. In previous studies, we demonstrated that the T-dominant Brucella antigens bacterioferritin (BFR) and P39 administered either as CpG adjuvant recombinant proteins or as naked-DNA plasmids induced a specific Th1-biased immune response in mice. In order to improve the protection conferred by the BFR and P39 vaccines and to evaluate the additive role of antilipopolysaccharide (anti-LPS) antibodies, we used live attenuated Yersinia enterocolitica serotypes O:3 and O:9 as delivery vectors for naked-DNA plasmids encoding these BFR and P39 antigens. Following two intragastric immunizations in BALB/c mice, the Yersinia vectors harboring a DNA vaccine encoding BFR or P39 induced antigen-specific serum immunoglobulin and Th1-type responses (both lymphocyte proliferation and gamma interferon production) among splenocytes. Moreover, as expected, antibodies recognizing Brucella abortus 544 lipopolysaccharide were detected in O:9-immunized mice but not in O:3-treated animals. Animals immunized with O:9 organisms carrying pCI or with O:9 organisms alone were found to be significantly resistant to infection by B. abortus 544. Our data demonstrated that pCI plasmids encoding BFR or P39 and delivered with live attenuated strains of Yersinia O:3 or O:9 can trigger Th1-type responses. The fact than only O:9 vectors induced a highly significant protective immunity against B. abortus 544 infection pointed out the crucial role of anti-LPS antibodies in protection. The best protection was conferred by a serotype O:9 strain carrying pCIP39, confirming the importance of the P39 T-cell antigen in this mechanism.
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PMID:Yersinia enterocolitica as a vehicle for a naked DNA vaccine encoding Brucella abortus bacterioferritin or P39 antigen. 1189 55

The effect of Brucella on the generation of microbicidal reactive oxygen and nitrogen metabolites by bovine peripheral polymorphonuclear cells (PMNs) was investigated. The PMNs were recovered from the peripheral blood of control calves and experimental calves previously vaccinated against brucellosis. Significantly larger quantities of NO and H2O2 were generated by PMNs from control and experimental calves following activation by heat-killed whole cells or outer membrane protein of Brucella abortus than by non-activated cells (p<0.05-0.01). In contrast, generation of H2O2 and NO decreased when PMNs were exposed to the lipopolysaccharide of Brucella. However, the generation of H2O2 and NO by activated PMNs from the control and experimental calves did not differ significantly.
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PMID:The effect of Brucella abortus on hydrogen peroxide and nitric oxide production by bovine polymorphonuclear cells. 1192 86

Although some ELISA tests using cytoplasmic or outer membrane antigens of Brucella have been developed to improve the diagnosis of canine brucellosis, the performance of these assays has not been compared. In the present study three ELISA tests using lipopolysaccharide (LPS)-free cytoplasmic proteins (CPs) of Brucella abortus, the lumazine synthase (LS) of Brucella spp. or a hot-saline (HS) extract of Brucella canis containing outer membrane antigens were used to test sera from dogs with suspected or confirmed brucellosis (n=36) and from dogs with pathological conditions other than brucellosis (n=212). In the first group the proportion of positive results was 92, 92 and 81% for the ELISAs with HS, CP and LS, respectively, and 94% of the samples were positive by at least one ELISA test. Three dogs that were negative by agglutination (2ME-RSAT) had a positive result by at least one ELISA, and this discrepancy was attributed to the lower analytical sensitivity of agglutination tests. This hypothesis was confirmed by a serological follow-up of seven dogs recently infected with B. canis in three of which the illness was diagnosed earlier by one or more ELISA tests than by 2ME-RSAT. Among dogs having pathological conditions other than brucellosis, specificities were 94.3, 96.7 and 96.7% for the ELISAs with HS, CP and LS, respectively. This study shows that HS-ELISA and CP-ELISA are highly specific and sensitive for the diagnosis of canine brucellosis and can detect the infection by B. canis shortly after the exposure to the pathogen.
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PMID:Comparative performance of tests using cytosolic or outer membrane antigens of Brucella for the serodiagnosis of canine brucellosis. 1222 Aug 11

Brucella abortus S19 is the vaccine most frequently used against bovine brucellosis. Although it induces good protection levels, it cannot be administered to pregnant cattle, revaccination is not advised due to interference in the discrimination between infected and vaccinated animals during immune-screening procedures, and the vaccine is virulent for humans. Due to these reasons, there is a continuous search for new bovine vaccine candidates that may confer protection levels comparable to those conferred by S19 but without its disadvantages. A previous study characterized the phenotype associated with the phosphoglucomutase (pgm) gene disruption in Brucella abortus S2308, as well as the possible role for the smooth lipopolysaccharide (LPS) in virulence and intracellular multiplication in HeLa cells (J. E. Ugalde, C. Czibener, M. F. Feldman, and R. A. Ugalde, Infect. Immun. 68:5716-5723, 2000). In this report, we analyze the protection, proliferative response, and cytokine production induced in BALB/c mice by a deltapgm deletion strain. We show that this strain synthesizes O antigen with a size of approximately 45 kDa but is rough. This is due to the fact that the deltapgm strain is unable to assemble the O side chain in the complete LPS. Vaccination with the deltapgm strain induced protection levels comparable to those induced by S19 and generated a proliferative splenocyte response and a cytokine profile typical of a Th1 response. On the other hand, we were unable to detect a specific anti-O-antigen antibody response by using the fluorescence polarization assay. In view of these results, the possibility that the deltapgm mutant could be used as a vaccination strain is discussed.
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PMID:Evaluation of Brucella abortus phosphoglucomutase (pgm) mutant as a new live rough-phenotype vaccine. 1457 45

Initial host defense to bacterial infection is executed by innate immunity, and therefore the main goal of this study was to examine the contribution of Toll-like receptors (TLRs) during Brucella abortus infection. CHO reporter cell lines transfected with CD14 and TLRs showed that B. abortus triggers both TLR2 and TLR4. In contrast, lipopolysaccharide (LPS) and lipid A derived from Brucella rough (R) and smooth (S) strains activate CHO cells only through TLR4. Consistently, macrophages from C3H/HePas mice exposed to R and S strains and their LPS produced higher levels of tumor necrosis factor alpha (TNF-alpha) and interleukin-12 compared to C3H/HeJ, a TLR4 mutant mouse. The essential role of TLR4 for induction of proinflammatory cytokines was confirmed with diphosphoryl lipid A from Rhodobacter sphaeroides. Furthermore, to determine the contribution of TLR2 and TLR4 in bacterial clearance, numbers of Brucella were monitored in the spleen of C3H/HeJ, C3H/HePas, TLR2 knockout, and wild-type mice at 1, 3, and 6 weeks following B. abortus infection. Interestingly, murine brucellosis was markedly exacerbated at weeks 3 and 6 after infection in animals that lacked functional TLR4 (C3H/HeJ) compared to C3H/HePas that paralleled the reduced gamma interferon production by this mouse strain. Finally, by mass spectrometry analysis we found dramatic differences on the lipid A profiles of R and S strains. In fact, S lipid A was shown to be more active to trigger TLR4 than R lipid A in CHO cells and more effective in inducing dendritic cell maturation. In conclusion, these results indicate that TLR4 plays a role in resistance to B. abortus infection and that S lipid A has potent adjuvant activity.
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PMID:Role of Toll-like receptor 4 in induction of cell-mediated immunity and resistance to Brucella abortus infection in mice. 1468 95

Brucellosis control and eradication requires serological tests and vaccines. Effective classical vaccines (S19 in cattle and Rev 1 in small ruminants), however, induce antibodies to the O-polysaccharide of the lipopolysaccharide which may be difficult to distinguish from those resulting from infection and may thus complicate diagnosis. Rough attenuated mutants lack the O-polysaccharide and would solve this problem if eliciting protective immunity; the empirically obtained rough mutants 45/20 and RB51 have been used as vaccines. Strain 45/20 is reportedly unstable and it is not presently used. RB51 is increasingly used instead of S19 in some countries but it is rifampicin resistant and its effectiveness is controversial. Some controlled experiments have found good or absolute protection in adult cattle vaccinated orally (full dose) or subcutaneously (reduced dose) and in one field experiment, RB51 was reported to afford absolute protection to calves and to perform better than S19. Controlled experiments in calves, however, have shown reduced doses of RB51 to be ineffective, full doses only partially effective, and RB51 less effective than S19 against severe challenges. Moreover, other observations suggest that RB51 is ineffective when prevalence is high. RB51 is not useful in sheep and evidence in goats is preliminary and contradictory. Rough mutants obtained by molecular biology methods on the knowledge of the genetics and structure of Brucella lipopolysaccharide may offer alternatives. The B. abortus manBcore (rfbK) mutant seems promising in cattle, and analyses in mice suggest that mutations affecting only the O-polysaccharide result in better vaccines than those affecting both core and O-polysaccharide. Possible uses of rough vaccines also include boosting immunity by revaccination but solid evidence on its effectiveness, safety and practicality is not available.
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PMID:Rough vaccines in animal brucellosis: structural and genetic basis and present status. 1509 1

Human brucellosis can be acquired from infected animal tissues by ingestion, inhalation, or contamination of conjunctiva or traumatized skin by infected animal products. In addition, Brucella is recognized as a biowarfare threat agent. Although a vaccine to protect humans from natural or deliberate infection could be useful, vaccines presently used in animals are unsuitable for human use. We tested orally administered live, attenuated, purine auxotrophic B. melitensis WR201 bacteria for their ability to elicit cellular and humoral immune responses and to protect mice against intranasal challenge with B. melitensis 16M bacteria. Immunized mice made serum antibody to lipopolysaccharide and non-O-polysaccharide antigens. Splenocytes from immunized animals released interleukin-2 and gamma interferon when grown in cultures with Brucella antigens. Immunization led to protection from disseminated infection and enhanced clearance of the challenge inoculum from the lungs. Optimal protection required administration of live bacteria, was related to immunizing dose, and was enhanced by booster immunization. These results establish the usefulness of oral vaccination against respiratory challenge with virulent Brucella and suggest that WR201 should be further investigated as a vaccine to prevent human brucellosis.
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PMID:Oral vaccination with Brucella melitensis WR201 protects mice against intranasal challenge with virulent Brucella melitensis 16M. 1521 48


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