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

The O-specific polysaccharide obtained from the lipopolysaccharide of Shigella dysenteriae type 1 (Shigella shiga) by mild acid hydrolysis followed by fractionation on Sephadex G-50 was found to be identical to that desribed by Morgan's group and was composed of L-rhamnose, D-galactose and N-acetyl-D-glycosamine in a ratio 2:1:1. On the basis of methylation analysis data the polysaccharide was proved to be a linear chain of monosaccharide residues in pyranose forms substituted at position 3, except for that of galactose substituted at position 2. Selective cleavage, based on the N-deacetylation reaction of the polymer, together with determination of linkage configurations by chromic anhydride oxidation showed that the O-specific polysaccharide is built up of repeating tetrasaccharide units whose proposed structure is given below -3)-alpha-L-Rhap (1-3)-alpha-L-Rhap(1-2)-alpha-D-Galp(1-3)-alphapD-GlcNAcp(1- where RHAP = rhamnopyranose, Galp = galactopyranose, and GlcNAcp = N-acetyl-glucosamine. The present findings confirmed the considerations of Heidelberger on the substitution patterns of L-rhamnose and D-galactose residues from the results of serological studies.
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PMID:Somatic antigens of shigella. Structural investigation on the O-specific polysaccharide chain of Shigella dysenteriae type 1 lipopolysaccharide. 0 14

Murein lipoprotein from the outer membrane of Escherichia coli could be fixed to erythrocytes without pretreatment of the erythrocytes. Passive hemagglutination or immune hemolysis could thus be used as sensitive assays to determine antibodies against lipoprotein. In rabbit antisera prepared against whole cells of E. coli, Salmonella, Arizona, and Shigella antibodies against lipoprotein were present. The respective titers were lowest in encapsulated smooth strains and highest in rough mutants. Antisera against deep rough mutants showed even higher anti-lipoprotein titers than anti-R-lipopolysaccharide titers. Correspondingly,absorption of lipoprotein antibodies with enterobacterial strains was most pronounced with deep rough mutants and lowest with smooth strains. Lipoprotein becomes increasingly an immunogen as well as an antigen the more sugar residues are missing in the lipolysaccharide on the cell surface. In wild-type cells lipoprotein is buried in the outer membrane; its exposure in mutant cells is related to defects at the cell surface.
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PMID:Antigenic determinants of murein lipoprotein and its exposure at the surface of Enterobacteriaceae. 5 56

It is known that only certain strains of the family of Enterobacteriaceae, notably rough (R) mutants with the type R1 or R4 core, evoked antibodies in high titers against the common enterobacterial antigen (CA) after immunization of rabbits with heated cell suspensions. The present investigation deals with genetic and immunochemical aspects of certain R1 and R4 mutants isolated from Escherichia coli 08 and various Shigella serotypes which, unexpectedly, do not induce CA antibody formation. Immunochemical and genetical (transduction and conjugation) experiments revealed that the rough phenotype of these special mutants was evoked by a mutation of pyrE-linked rfa gene, called rfaL, which is involved in translocation of O-specific polysaccharides onto the lipopolysaccharide core. The transduction of the defective rfaL, allele into appropriate rough recipients results in transductants which have simultaneously lost the ability to evoke CA antibodies. This finding suggests that a close connection exists between the function of the rfaL gene and the expression of CA immunogenicity in R1 and R4 mutants. One of the strains synthesized neither O-hapten nor CA, suggesting a mutation in a region equivalent to the rfe genes of Salmonella.
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PMID:Role of a lipopolysaccharide gene for immunogenicity of the enterobacterial common antigen. 5 14

Immunochemical studies on Shigella sonnei and serotype 6 Shigella flexneri 0 antigens (lipopolysaccharides) and enterobacterial common antigen (ECA) isolated from Shigella sonnei were carried out. Oligosaccharide structure of 0-specific chain of serotype 6 Shigella fiexneri lipopolysaccharide was defined and beta-L-rhamnosyl-1,3-N-acetyl-D-galactosamin as immunodeterminant of type VI specificity was recognized. The structures of core regions of lipopolysaccharides isolated from R mutants of both Shigella subgroups were established. On the base of the serological and structural results it has been suggested that these core regions are identical and very close to RI core structure of E. coli C. The effective method of isolation and purification of enterobacterial common antigen from Shigella sonnei was elaborated and its immunological properties as well as chemical character defined.
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PMID:Immunochemical characteristics of Shigella sonnei and serotype 6 Shigella flexneri lipopolysaccharides and enterobacterial common antigen. 8 36

1. Protein extracts obtained from Salmonella minnesota Re mutant cells by treatment with EDTA/NaC1 solution contain a protein which exhibits high affinity to bacterial lipopolysaccharides. The isolation and partial characterization of this lipopolysaccharide-binding protein is described. 2. The protein was purified from EDTA extracts by a two-step procedure consisting of ion-exchange chromatography on CM-Sephadex and preparative polyacrylamide gel electrophoresis at pH 9.5. The yield of the total purification procedure was around 16%. 3. The resulting protein preparation was homogeneous on the basis of disc gel electrophoresis, dodecylsulfate gel electrophoresis, isoelectric focusing in polyacrylamide gel and immunoelectrophoresis. 4. The isoelectric point of the protein was found to be 10.3 at 4 degrees C. Its molecular weight determined by dodecylsulfate gel electrophoresis is 15000. Its amino acid composition is characterized by the absence of histidine and proline, a low content in tyrosine and high amounts of alanine, lysine, aspartic and glutamic acid residues, or their respective amides. 5. The lipopolysaccharide-protein association was shown to be mainly due to ionic interactions of the basic protein with negatively charged groups (probably phosphate and pyrophosphate groups) of the lipid A moiety. 6. Purified lipopolysaccharide-binding protein is immunogenic in rabbits, thus enabling the preparation of specific antiserum. 7. The protein is located at the surface of Salmonella minnesota Re mutant cells as revealed by antiserum absorption with total bacteria. Ferritin-labelling studies further demonstrated that it is evenly spread over the entire cell surface. 8. Comparative antiserum absorption studies using smooth and rough strains of Salmonella minnesota, Salmonella typhimurium, Escherichia coli, Klebsiella and Shigella revealed the presence of lipopolysaccharide-binding protein (or a serologically cross-reacting antigen) in most of the strains tested. From these results the protein can be considered as a common antigen of Enterobacteriaceae.
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PMID:A lipopolysaccharide-binding cell-surface protein from Salmonella minnesota. Isolation, partial characterization and occurrence in different Enterobacteriaceae. 11 33

In an attempt to develop a safe, proliferating, oral, attenuated vaccine against shigellosis, genes that control the synthesis of group- and type-specific somatic antigens of Shigella flexneri 2a were transferred via conjugation to a recipient strain of Escherichia coli. The resultant hybrid (E. coli expressing shigella surface antigens) vaccine strain, PGAI 42-1-15, believed to have a complete (smooth) lipopolysaccharide, was given to volunteers in two vaccination-challenge studies. The vaccine was well tolerated and gave evidence of intestinal proliferation. In trial no. 1, volunteers given two doses of vaccine one month apart were challenged after eight weeks with 10(4) virulent S. flexneri 2a. Attack rates were comparable in vaccinees (50%) and controls (40%). In trial no. 2, vaccinees were given three weekly doses of vaccine and were challenged four weeks later with a small inoculum (10(2)) of S. flexneri 2a. Again, attack rates among vaccinees (47%) and controls (39%) were similar. It is unclear why this theoretically ideal, live shigella vaccine failed to protect against S. flexneri 2a.
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PMID:Studies with a new generation of oral attenuated shigella vaccine: Escherichia coli bearing surface antigens of Shigella flexneri. 33 41

The specific polysaccharide was obtained from the lipopolysaccharide of Shigella newcastle by mild acid hydrolysis and further purified by permeation chromatography on Sephadex G-50. It was found to consist of L-rhamnose, 2-acetamido-2-deoxy-D-galactose, D-galacturonic acid residues and O-acetyl groups in the molar ratios of 2:1:1:1. On the basis of 1H and 13C nuclear magnetic resonance spectroscopy, methylation analysis, partial acid hydrolysis, Smith degradation, and chromium trioxide oxidation, the following structure can be assigned to the repeating oligosaccharide unit of the polysaccharide:-4)DGalA(beta 1-3)DGalNAc-(beta 1-2)LAc3Rha(alpha 1-2)LRha(alpha 1-, where GalA = galacturonic acid. GalNAc = N-acetylgalactosamine, Ac3Rha = 3-O-acetylrhamnose. The structural and immunochemical data presented prove that Sh. newcastle lipopolysaccharide belongs to a 'non-classical' type of somatic antigens with acidic O-specific polysaccharide chains.
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PMID:Somatic antigens of Shigella. The structure of the specific polysaccharide of Shigella newcastle (Sh. flexneri type 6) lipopolysaccharide. 38 Oct 1

Mice responded to lipopolysaccharide (LPS) with a dose-dependent, monophasic hypothermia reaching a maximum at 2 h postinjection. Degraded polysaccharide was not active; free lipid A, however, induced a similar pattern of hypothermia, indicating that the hypothermic principle of LPS was embedded within the lipid A component. The hypothermic response of mice to LPS was modified by prior exposure of the host to LPS. This altered reactivity was manifested by refractory periods (early and late tolerance), in which animals no longer responded with hypothermia, or a hyperreactive phase (hypersensitivity), in which hypothermic responses were greatly augmented upon LPS challenge. Thus, tolerance observed 24 h after a single injection of LPS (early tolerance) was followed, on further LPS challenge, by an enhanced hypothermic responses reaching a maximum on day 4. Further daily exposure of the animals to LPS eliminated hyperreactivity and led to the establishment of a late tolerance maximally expressed on day 8. Hyperreactivity could also be evoked on day 4 after a single injection of LPS. Mice pretreated with Salmonella S- and R-form LPS or free lipid A (Salmonella) demonstrated tolerance and hyperreactivity to both homologous and heterologous challenge. In addition, complete cross-tolerance was observed with S-form LPS derived from Shigella. It was concluded that the differential effects of LPS on host responses (tolerance and hyperreactivity) were due to lipid A.
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PMID:Lipid A-induced tolerance and hyperreactivity to hypothermia in mice. 63 75

Immunoprophylaxis for bacterial enteric diseases is hindered because the protective immune mechanism(s) against nontyphoidal salmonellae or shigellae in humans are not established. On the basis of the similarities between the clinical signs, epidemiology, pathogenesis, and pathology of as well as protective immunity to salmonellae and shigellae, we propose that serum IgG antibodies to the O-specific polysaccharide (O-SP) of their lipopolysaccharides (LPSs) will confer protective immunity to these two pathogens. Critical to this notion is that (1) the virulence of these two pathogens requires full expression of their LPS; (2) active or passive immunization with serum IgG O-SP antibodies confers protection of mice against Salmonella typhimurium (there are no comparable data for humans); and (3) in humans, convalescence from shigellosis confers type (O-SP) -specific protective immunity, and indirect evidence shows a correlation between the level of serum LPS antibodies and resistance to shigellosis. We designed conjugate vaccines to elicit high levels of long-lived serum IgG O-SP antibodies to nontyphoidal salmonellae and shigellae to test this hypothesis.
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PMID:Hypothesis for vaccine development: protective immunity to enteric diseases caused by nontyphoidal salmonellae and shigellae may be conferred by serum IgG antibodies to the O-specific polysaccharide of their lipopolysaccharides. 138 21

The construction and characterization of EcSf2a-2, an aroD-deleted Escherichia coli-Shigella hybrid vaccine carrying chromosomal and plasmid genes from Shigella flexneri and expressing S. flexneri 2a somatic antigen in association with E. coli K12 core are described. Expression of hybrid lipopolysaccharide and deletion of aroD resulted in the attenuation of phenotypic characteristics associated with pathogenicity. The addition of an aroD deletion results in a requirement for an aromatic precursor of para-aminobenzoic acid (PABA), an essential bacterial metabolite not present in mammalian tissues. The biosynthesis of hybrid somatic antigen prevents expression of a Sereny-positive reaction by invasive bacteria capable of expressing a plaque-positive phenotype. A functional kcpA gene is required for expression of the plaque-positive phenotype. The presence of an aroD deletion does not interfere with expression of an invasive phenotype; however, in bacteria containing a functional kcpA gene, replication and spread by invading bacteria are limited, preventing development of the plaque-positive phenotype.
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PMID:Genotypic and phenotypic characterization of an aroD deletion-attenuated Escherichia coli K12-Shigella flexneri hybrid vaccine expressing S. flexneri 2a somatic antigen. 144 32


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