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

The virulence factors of the lipopolysaccharide of Shigella species bacteria include the endotoxic activities of the lipid A component of the molecule and the ability of the polysaccharide chain--the core and the O-antigenic polysaccharide--to provide the bacterium with resistance to host defense mechanisms such as opsonization, phagocytosis, and intracellular killing. Structural features of the lipopolysaccharides of four Shigella species-S. dysenteriae, S. flexneri, S. boydii, and S. sonnei--are described.
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PMID:The lipopolysaccharide of Shigella bacteria as a virulence factor. 171 Aug 16

Although the common mucosal immune system has generally been considered to have only short-term memory, recent data suggest that long-term memory exists for Shigella virulence plasmid antigens. Because such antigens might cross-react with environmental antigens, we investigated milk for the persistence of antibodies to the specific Shigella lipopolysaccharide (LPS) antigens. Enzyme-linked immunosorbent assays to detect secretory immunoglobulin A (sIgA) against Shigella flexneri and Shigella sonnei LPS in milk samples were developed; 15 random milk samples tested on different days correlated from one day to the next (P = 0.0001). Of 18 Mexican mothers, 18 (100%) had one or more milk samples positive for anti-S. flexneri LPS, 14 (78%) had one or more milk samples positive for anti-S. sonnei LPS, and 14 (78%) had one or more milk samples positive for both. Of 27 Houston mothers, 16 (59%) had one or more milk samples positive for anti-S. flexneri LPS, 7 (26%) had one or more milk samples positive for anti-S. sonnei LPS, and 5 (19%) had one or more milk samples positive for both. Mexican mothers were significantly more likely than Houston mothers to have at least one sample with a positive titer for anti-S. flexneri LPS (P less than 0.02) and at least one sample with a positive titer for anti-S. sonnei LPS (P less than 0.002). Although the Houston women had a lower rate of titer positivity for both Shigella species, the rate was too high to be consistent with short-lived mucosal immunity. It is unlikely that 18 of the 27 Houston women had shigellosis during or just prior to lactation. The data suggest that there exists a long-term hormonally driven memory in the secretory immune system for Shigella spp.
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PMID:Evidence for long-term memory of the mucosal immune system: milk secretory immunoglobulin A against Shigella lipopolysaccharides. 177 68

20 Mexico City and 23 Houston, Texas colostrum samples, and 21 Mexican and 25 Houston mature milk samples were analyzed by ELISA and Western blot, respectively, for antibodies against the virulence plasmid of Shigella flexneri serotype 5 strain M9OT. The method involved comparing water extracts of milk in ELISA and Western blot determinations of antigens against shigella flexneri strain M9OT which is fully virulent, to those against M9OT A2 which lacks the virulence plasmid. While there are at least 37 know distinct lipopolysaccharide antigens on different strains of the 4 species of Shigella, all contain the same plasmid conferring virulence, the ability of the bacteria to invade mammalian cells. This provided a universal test for antigens to Shigella. Western blots showed antibodies in all 21 Mexican women and in 40% of 25 Houston women. Plasmid antibodies were detected by ELISA in all 20 Mexican colostrum samples and in 52% of 23 Houston colostrum samples. After 8 days of lactation, 93% of the Mexican and 46% of the Houston milk samples were positive. The actual protective factor in human milk against Shigella bacteria is unknown: these findings suggest a mechanism for protection against all serotypes of shigella. The high prevalence of antibodies against Shigella found in Houston women was attributed to infection in the distant past.
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PMID:Milk secretory IgA related to Shigella virulence antigens. 180 12

The background for developing conjugate vaccines for shigellosis composed of the O-specific polysaccharide (O-SP) bound to a protein is described elsewhere (C. Y. Chu, R. Schneerson, and J. B. Robbins, submitted for publication). Briefly, there is direct evidence for type (lipopolysaccharide [LPS])-specific protection after infection with the wild type or with attenuated strains of shigellae. Prospective studies of Israeli armed forces recruits show a correlation between preexisting serum immunoglobulin G (IgG) LPS antibodies and resistance to shigellosis (D. Cohen, M. S. Green, C. Block, R. Slephon, and I. Ofek, J. Clin. Microbiol. 29:386-389, 1991). In order to elicit IgG LPS-specific antibodies to Shigella dysenteriae type 1, the O-SP of this pathogen was purified and bound to tetanus toxoid (TT) by three schemes. The most immunogenic used a modification of a published method (C. Y. Chu, R. Schneerson, J. B. Robbins, and S. C. Rastogi, Infect. Immun. 40:245-256, 1983). The resultant O-SP-TT conjugates were stable and elicited high levels of IgG O-SP antibodies and booster responses in young mice when injected subcutaneously in saline at 1/10 the proposed human dose. Adsorption onto alum or concurrent administration with monophosphoryl lipid A enhanced both the IgG and IgM antibody responses to the O-SP of the conjugate; both the nonadsorbed and adsorbed conjugates elicited higher rises of IgG than of IgM antibodies. Clinical evaluations of S. dysenteriae type 1 O-SP-TT conjugates are planned.
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PMID:Preparation, characterization, and immunogenicity of conjugates composed of the O-specific polysaccharide of Shigella dysenteriae type 1 (Shiga's bacillus) bound to tetanus toxoid. 193 3

Although antibodies to the lipopolysaccharide antigens of Shigella have been demonstrated in human milk, such antibodies do not explain the putative protective effect of breast-feeding against symptomatic Shigella infection. Shigella species do not share related lipopolysaccharides, but they do possess closely related virulence plasmids that code for the proteins essential for cell invasion. We therefore sought to determine the frequency, amount, and duration of excretion of human milk antibodies to these shared virulence plasmid-associated antigens in populations of different rates of Shigella infection frequency (Mexico City, high; Houston, low). Such antibodies were present in the milk of virtually all the Mexican women but also were present in a large proportion of milk samples from the women living in Houston. The amounts of these antibodies were highest in colostrum but after 2 weeks of lactation fell to stable levels. The frequency and persistence of these antibodies in the milk of the women from Houston suggest that the memory and drive for secretion of these antibodies is extremely long lived.
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PMID:Human milk secretory immunoglobulin A to Shigella virulence plasmid-coded antigens. 198 95

In this study the ability of strains of Shigella dysenteriae serotype 1 to agglutinate mammalian erythrocytes is attributed to the polysaccharide fraction of bacterial-cell lipopolysaccharide (LPS). LPS obtained from a rough, mutant strain of S. dysenteriae serotype 1, lacking the O-antigen polysaccharide side-chain, did not agglutinate erythrocytes, clearly demonstrating a link between O-antigen polysaccharides and haemagglutinating activity (HA). Strains of S. dysenteriae serotype 1 adhered well to cultured Henle Intestinal 407 cells, whereas rough strains adhered poorly. Pre-treatment of bacteria with LPS-specific antisera inhibited both HA and binding to cultured human-intestinal cells. The contribution of the polysaccharide side-chain and its associated HA--which appear to facilitate binding to cultured cells--to bacterial attachment to colonocytes and to the pathogenesis of shigellosis in vivo needs to be confirmed in animal studies.
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PMID:The association of haemagglutination and adhesion with lipopolysaccharide of Shigella dysenteriae serotype 1. 203 May 1

The performance of enzyme immunoassays (EIAs) with use of O-antigen-containing lipopolysaccharides (LPSs) extracted with phenol-water from Shigella dysenteriae type 1, Shigella flexneri serotypes 1a-5b, and Shigella sonnei for determination of the serum antibody responses after onset of bacillary dysentery is reviewed. For the purpose of several studies, serum samples from a total of 175 Vietnamese and 47 Swedish patients, for whom Shigella species had been isolated from fecal specimens, were obtained at various intervals until less than or equal to 1 year after the onset of infection. Titers of antibodies in serum samples from infected patients were compared with those in serum samples from healthy control subjects; the combined control population of all studies comprised 426 Vietnamese and 154 Swedes. The sensitivity of the EIAs ranged from 78% to 100% for patients whose fecal culture was positive for Shigella. For diagnosis of S. flexneri, a species-specific but no serotype-specific assay based on LPS antigens is possible. Among Vietnamese patients the EIA with use of S. flexneri was sensitive and diagnostic only for children less than 3 years of age, most likely because healthy older Vietnamese children and adults have high titers of antibody to the O-antigens of S. flexneri. Among Swedish patients the same EIA was diagnostic for adults as well as children. Increased titers of IgA in the early phase and of IgG in the convalescent phase, as determined by EIA, were the best indicators of infection due to Shigella species.
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PMID:Shigellosis in Vietnam: seroepidemiologic studies with use of lipopolysaccharide antigens in enzyme immunoassays. 204 43

Only indirect evidence has been cited to document that lipopolysaccharide-mediated virulence at the bacterial level and serum antibodies to the O-specific side chain of the lipopolysaccharide molecule may prevent shigellosis. Our proposed use of the B subunit of Shiga toxin as a carrier protein is based upon evidence (even more indirect) that serum antitoxin may reduce the severity of dysentery and diarrhea. Because animal models of disease may provide information inapplicable to the prediction of vaccine-induced protective immunity, we suggest that clinical trials in the population at risk should be started after successful completion of the safety and immunogenicity phases of vaccine development in laboratory animals and in the target population. Clinical studies of shigella vaccines are difficult because of the many causes of dysentery in a population with a high rate of intestinal disease.
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PMID:O-specific side-chain toxin-protein conjugates as parenteral vaccines for the prevention of shigellosis and related diseases. 204 64

Shigellosis is a major cause of infant morbidity and mortality in developing countries. To find immunological correlates of specific protection against shigellosis, we examined chronological samples of sera, stool extracts, duodenal aspirates, and saliva samples from 39 adults and 22 children with shigellosis from Peru for the presence of specific antibody to invasion plasmid antigens (Ipa) common to all virulent Shigella strains, by using both a whole-organism enzyme-linked immunosorbent assay (ELISA) and a Western blot (immunoblot) assay. Antibody responses to lipopolysaccharide (LPS) from Shigella serotypes both homologous and heterologous to the infecting strain were also determined by ELISA. ELISAs showed that the highest serum immunoglobulin G (IgG) antibody titers to Shigella whole organisms both with and without surface Ipa were found in adults and malnourished children, the two groups with the shortest and longest durations of disease, respectively. Mucosal IgA antibody titers to Shigella strains decreased over time to a much greater extent than serum IgG titers, and IgA to Ipa in mucosal secretions was found in adults and well-nourished children but not in malnourished children. The presence of mucosal antibody to Ipa may limit the spread and severity of the infection, as indicated by the prolonged illness observed in malnourished children who have no significant mucosal antibody to Shigella Ipa. Serum antibody titers to the Ipa antigens were high relative to anti-Shigella LPS antibody titers, especially in pediatric patients. In contrast to the anti-Ipa responses observed, no differences in antibody responses to LPS in children compared by nutritional status were found. High levels of serum and mucosal cross-reacting antibody to heterologous serotype LPS were found between Shigella flexneri serotypes 1a and 2a. Different patterns of immune response to Ipa proteins and LPS that may aid in the definition of Shigella antigens important in host protection were observed in adults, well-nourished children, and malnourished children.
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PMID:Prospective study of systemic and mucosal immune responses in dysenteric patients to specific Shigella invasion plasmid antigens and lipopolysaccharides. 205 Apr 2

As an approach to the development of attenuated strains, thymine-requiring (Thy-) and temperature-sensitive (Ts-) single and double mutants of Shigella flexneri Y have been isolated by u.v. mutagenesis and selection. The mutants retained the 140 MDa plasmid, were Sereny-negative and avirulent in 'conditioned' rabbits and in monkeys. Rabbits and monkeys immunized orally with two doses of the mutants were solidly protected against disease and lethality when challenged with the homologous virulent strain. The immunized animals had higher levels of antibodies reactive to the lipopolysaccharide of the wild type strain and also a shorter duration of shedding of the challenge bacteria. It was concluded that Thy- and Ts- mutants of Shigella spp. are highly attenuated and immunogenic to be considered for further studies towards the development of vaccine candidates.
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PMID:Protection of adult rabbits and monkeys from lethal shigellosis by oral immunization with a thymine-requiring and temperature-sensitive mutant of Shigella flexneri Y. 218 82


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