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)

Epidemiologic and experimental data provide evidence that a critical level of serum immunoglobulin G (IgG) antibodies to the surface polysaccharide of Vibrio cholerae O1 (lipopolysaccharide) and of Vibrio cholerae O139 (capsular polysaccharide [CPS]) is associated with immunity to the homologous pathogen. The immunogenicity of polysaccharides, especially in infants, may be enhanced by their covalent attachment to proteins (conjugates). Two synthetic schemes, involving 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) as activating agents, were adapted to prepare four conjugates of V. cholerae O139 CPS with the recombinant diphtheria toxin mutant, CRMH21G. Adipic acid dihydrazide was used as a linker. When injected subcutaneously into young outbred mice by a clinically relevant dose and schedule, these conjugates elicited serum CPS antibodies of the IgG and IgM classes with vibriocidal activity to strains of capsulated V. cholerae O139. Treatment of these sera with 2-mercaptoethanol (2-ME) reduced, but did not eliminate, their vibriocidal activity. These results indicate that the conjugates elicited IgG with vibriocidal activity. Conjugates also elicited high levels of serum diphtheria toxin IgG. Convalescent sera from 20 cholera patients infected with V. cholerae O139 had vibriocidal titers ranging from 100 to 3,200: absorption with the CPS reduced the vibriocidal titer of all sera to < or =50. Treatment with 2-ME reduced the titers of 17 of 20 patients to < or =50. These data show that, like infection with V. cholerae O1, infection with V. cholerae O139 induces vibriocidal antibodies specific to the surface polysaccharide of this bacterium (CPS) that are mostly of IgM class. Based on these data, clinical trials with the V. cholerae O139 CPS conjugates with recombinant diphtheria toxin are planned.
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PMID:Vibrio cholerae O139 conjugate vaccines: synthesis and immunogenicity of V. cholerae O139 capsular polysaccharide conjugates with recombinant diphtheria toxin mutant in mice. 1094 22

In the present investigations we aimed to study the effect of Shigella sonnei lipopolysaccharide (LPS) on delayed type hypersensitivity (DTH) to non-bacterial antigen in CBA mice. These experiments showed that intraperitoneal injection of phenol-water extracted LPS and avirulent S. sonnei did not affect the level of DTH. However, an injection of avirulent bacteria and LPS treated with 2-mercaptoethanol reduced significantly the levels of DTH. Gel filtration of redox-reactivated LPS through Sephadex G-200 shows that LPS contains three immunosuppressive components: approximately 800 kDa and higher, 150-200 and 50-70 kDa. These components differed by their specificity and heat-sensitivity.
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PMID:The immunosuppressive activity of chemically modified lipopolysaccharide of Shigella sonnei. 1171 60

A sensitive method has been developed which permits comparative analysis of IgM and IgG antibody specificity against lipopolysaccharide (LPS) antigen. It is based on hemolysis of LPS-coated red blood cells and on its inhibition by homologous and heterologous LPS. By appropriate use of anti-immunoglobulin sera, indirect (facilitated) lysis due to IgG antibodies is obtained, whereas IgM gives direct lysis and is 2-mercaptoethanol-sensitive. IgG can be analyzed either by facilitation with a rabbit anti-mouse Ig or with anti-allotype sera. By use of anti-allotype sera in F1 hybrids, both parental antibody types can be studied separately. Antibodies of either class from individual mice may display different cross-reactivity patterns. Furthermore, for IgM and IgG within a given serum, both similarities and differences have been found. Some of the cross-reactivity patterns have been followed over one year. With few exceptions, individual patterns remained constant throughout this period.
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PMID:Cross-reactivity patterns of IgM and IgG anti-lipopolysaccharide antibodies in individual mice. 1199 36

Recently, we demonstrated that the control of cytosolic and mitochondrial redox balance and oxidative damage is one of the primary functions of NADP(+)-dependent isocitrate dehydrogenase (ICDH) through to supply NADPH for antioxidant systems. NO donors such as S-nitrosothiols, diethylamine NONOate, spermine NONOate, and 3-morpholinosydnomine N-ethylcarbamide (SIN-1)/superoxide dismutase inactivated ICDH in a dose- and time-dependent manner. The inhibition of ICDH by S-nitrosothiol was partially reversed by thiol, such as dithiothreitol or 2-mercaptoethanol. Loss of enzyme activity was associated with the depletion of the cysteine-reactive 5,5'-dithiobis-(2-nitrobenzoate) and the loss of fluorescent probe N,N'-dimethyl-N(iodoacetyl)-N'-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) ethyleneamine accessible thiol groups. Using electrospray ionization mass spectrometry with tryptic digestion of protein, we found that nitric oxide forms S-nitrosothiol adducts on Cys305 and Cys387. These results indicate that S-nitrosylation of cysteine residues on ICDH is a mechanism involving the inactivation of ICDH by NO. The structural alterations of modified enzyme were indicated by the changes in protease susceptibility and intrinsic tryptophan fluorescence. When U937 cells were incubated with 200 microM SNAP for 1 h, a significant decrease in both cytosolic and mitochondrial ICDH activities were observed. Furthermore, stimulation with lipopolysaccharide significantly decreased intracellular ICDH activity in RAW 264.7 cells, and this effect was blocked by NO synthase inhibitor N(omega)-methyl-L-arginine. This result indicates that ICDH was also inactivated by endogenous NO. The NO-mediated damage to ICDH may result in the perturbation of cellular antioxidant defense mechanisms and subsequently lead to a pro-oxidant condition.
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PMID:Inactivation of NADP(+)-dependent isocitrate dehydrogenase by nitric oxide. 1236 3

We previously reported that anti-trinitrophenyl (TNP) antibody production in murine splenic B cells stimulated with TNP-lipopolysaccharide in vitro was promoted by sodium butyrate (NaBu) in an IL-2-dependent manner. In the present study, we found that the effect of NaBu plus IL-2 was markedly augmented by 2-mercaptoethanol (2-ME), which showed a slight or null effect on the response of untreated, IL-2-treated or NaBu-treated B cells, as assessed by both anti-TNP plaque-forming cell assay and anti-TNP IgM ELISA. Other thiol compounds such as dithiothreitol, cysteamine and reduced glutathione (GSH) also had this activity. 2-ME enhanced the anti-TNP antibody production induced by other short-chain fatty acids with three to five carbon atoms plus IL-2. The proliferation of B cells was significantly inhibited by NaBu or NaBu plus IL-2, and the proliferation was completely restored by the simultaneous addition of 2-ME. These results demonstrate that 2-ME markedly enhanced anti-TNP antibody production in murine B cells induced by NaBu plus IL-2 and suggest that the effect of 2-ME is at least partly due to its blocking activity of the growth-inhibitory action of NaBu.
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PMID:Augmentation by 2-mercaptoethanol of in vitro anti-TNP antibody production induced by butyrate plus IL-2 in murine splenic B cells. 1468 96

Iron regulatory protein-1 (IRP-1) is a bifunctional [4Fe-4S] protein that functions as a cytosolic aconitase or as a trans-regulatory factor controlling iron homeostasis at a post-transcriptional level. Because IRP-1 is a sensitive target protein for nitric oxide (NO), we investigated whether this protein is nitrated in inflammatory macrophages and whether this post-transcriptional modification changes its activities. RAW 264.7 macrophages were first stimulated with interferon-gamma and lipopolysaccharide (IFN-gamma/LPS) and then triggered by phorbol 12-myristate 13-acetate (PMA) in order to promote co-generation of NO* and O*2-.. IRP-1 was isolated by immunoprecipitation and analyzed for protein-bound nitrotyrosine by Western blotting. We show that nitration of endogenous IRP-1 in NO-producing macrophages boosted to produce O*2- was accompanied by aconitase inhibition and impairment of its capacity to bind the iron-responsive element (IRE) of ferritin mRNA. Lost IRE-binding activity was not recovered by exposure of IRP-1 to 2% 2-mercaptoethanol and was not due to protein degradation. Inclusion of cis-aconitate with cell extract to stabilize the [4Fe-4S] cluster of holo-IRP-1 rendered protein insensitive to nitration by peroxynitrite, suggesting that loss of [Fe-S] cluster and subsequent change of conformation are prerequisites for tyrosine nitration. IRP-1 nitration was strongly reduced when IFN-gamma/LPS/PMA-stimulated cells were incubated with myeloperoxidase inhibitors, which points to the contribution of the nitrite/H2O2/peroxidase pathway to IRP-1 nitration in vivo. Interestingly, under these conditions, IRP-1 recovered full IRE binding as assessed by treatment with 2% 2-mercaptoethanol. Peroxidase-mediated nitration of critical tyrosine residues, by holding IRP-1 in an inactive state, may constitute, in activated macrophages, a self-protecting mechanism against iron-induced toxicity.
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PMID:Endogenous nitration of iron regulatory protein-1 (IRP-1) in nitric oxide-producing murine macrophages: further insight into the mechanism of nitration in vivo and its impact on IRP-1 functions. 1525 60

Methods to assess immunocompetence requiring only a single sample are useful in comparative studies where practical considerations prevent holding or recapturing individuals. The assay for natural antibody-mediated complement activation and red blood cell agglutination described here, requiring approximately 100 microl of blood, is highly repeatable. The effects of complement deactivation, 2-mercaptoethanol (2-ME), age, and lipopolysaccharide (LPS)-induced sickness response were examined to validate comparisons among diverse avian species. Complement deactivation by heating significantly reduces lysis and treatment with 2-ME reduces both lysis and agglutination. Lysis and agglutination both increase with age in chickens; LPS treatment does not influence these variables in 11-week-old chickens. In a comparison of 11 species, both lysis (0.0-5.3 titers) and agglutination (1.8-8.0 titers) vary significantly among species. Accordingly, this assay can be used to compare constitutive innate humoral immunity among species and with respect to age, sex, and experimental treatments within populations.
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PMID:A hemolysis-hemagglutination assay for characterizing constitutive innate humoral immunity in wild and domestic birds. 1557 75

With the goal of providing an additional tool for controlling bovine brucellosis in Brazil and evaluating the full calf dose in adult cattle, the efficacy of the rough Brucella abortus strain RB51 vaccine was tested in heifers. Thirty-three females of approximately 24 months of age were divided in two groups: one group (n=20) received the RB51 vaccine and the other group (n=13) were used as non-vaccinated control. Animals in the vaccinated group were split in two sub-groups. One sub-group (n=12) was vaccinated subcutaneously with 1.5x10(10) colony forming units (CFU) of RB51 at Day 0 of the experiment and the other sub-group (n=8) was vaccinated subcutaneously with 1.6x10(10) CFU of RB51 at 60 days of gestation (Day 260 of the experiment). All cattle were challenged between 6 and 7 months of pregnancy with 3x10(8) CFU of the virulent strain 2308 of B. abortus by the conjunctival route. Vaccination with RB51 vaccine did not result in the production of any antibodies against the O-side chain of lipopolysaccharide (LPS), as measured by conventional serological tests (rose bengal plate agglutination test (RBPAT), standard tube agglutination test (STAT), and 2-mercaptoethanol test (2ME)). A total of 25% cumulative incidence of abortions was found in the vaccinated group, whereas in the control group the cumulative incidence was 62%. B. abortus RB51 was not isolated from any sample, and no abortions were produced by RB51 vaccination of females at 60 days of pregnancy. The results indicate that vaccination with RB51 prevented 59.4% of abortions, 58.6% of cow infections, and 61.0% of fetal infections. The relative risk (RR) revealed that non-vaccinated animals have 2.462 (95% CI 1.029-5.889) times higher risk of aborting than RB51-vaccinated animals.
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PMID:Efficacy of strain RB51 vaccine in heifers against experimental brucellosis. 1671 34

Porcine brucellosis is one of the most important zoonoses in this country. Currently, there is no control program for porcine brucellosis in Argentina and the epidemiological situation is still unknown. The purpose of our study was to detect anti-Brucella spp. antibodies in swine in the southwest of the Buenos Aires province and the east of the La Pampa province. Blood samples were obtained when animals were slaughtered. The presence of anti-brucella antibodies was studied by the buffered plate agglutination test (BPA), the tube agglutination test (SAT), the 2-mercaptoethanol (2-ME) agglutination test and indirect ELISA tests, using the cytosolic fraction from Brucella abortus S19 (CYT), and lipopolysaccharide (LPS)-free cytosolic proteins (CP). Out of a total of 325 samples analyzed, 17.8% reacted positively to BPA, 13.8% to SAT, 8.0% to 2-ME, 21.0% to ELISA-CYT and 10.0% to ELISA-CP. These results agree with the few data available in our country and suggest that brucellosis screening should be extended to other regions.
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PMID:[Detection of anti-Brucella spp. antibodies in swine by agglutination techniques and indirect ELISA in the Buenos Aires and La Pampa provinces, Argentina]. 1703 54

Effects of swainsonine (SW; 8alpha, beta-indolizidine-1alpha, 2alpha, 8-triol from Locoweed) on the humoral immune responses of lipopolysaccharide (LPS) were studied in ICR mice. Mice were divided into 4 groups (10mice/group), and LPS was given to each mouse 1 hr after i.p. injection with 3.7 mg/kg of swainsonine, by i.p. injection twice a week for 14 days at a dose of 2 mg/kg. Humoral immune responses were evaluated by hemagglutination (HA) titer and splenic plaque forming cells (PFC). The results of this study were summarized as follows: Mice administrated each of LPS and SW showed significant enhancement of the weight ratios of spleen to body, HA titer, 2-mercaptoethanol-resistant HA (MER-HA) titer and PFC compared with those in controls. However, the LPS plus SW treatment decreased HA titer, MER-HA titer and PFC corresponding to humoral immunity, as compared with those in the mice treated with LPS alone. These findings indicated that LPS significantly enhanced humoral immune responses, but their enhancement effects were lowered somewhat by SW.
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PMID:Effects of swainsonine on the humoral immune response of lipopolysaccharide. 1898 57


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