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At least 217 records · Page 12Linked to original sources
PubMed2002

Ordering in aqueous polysaccharide solutions. I. Dielectric relaxation in aqueous solutions of a triple-helical polysaccharide schizophyllan.

Deuterium oxide solutions of a triple-helical polysaccharide schizophyllan, undergoing an order-disorder transition centered around 17 degrees C, were studied by the time-domain reflectometry (TDR) to obtain dielectric dispersions in the solution and frozen states. In the solution state, the dispersion below the transition temperature is resolved in three dispersions (relaxation times at 0 degrees C) ascribed to side chain glucose residue (1; 102 ns), structured water (s; 2.0 ns) and bulk water (h), respectively, from low to high frequencies. Bulk water is divided into slow water (h2; 0.04 ns) and free or pure water (h1; 0.02 ns). Above the transition temperature structured water almost disappears and is compensated by slow water. Structured water is similar to bound water for proteins but different from it because of this transition behavior. Another dispersion (l) seen at the lowest frequency is assigned to the rotation of side-chain glucose residue coupled with hydrated water. Parts of this dispersion and structured water are suggested to constitute bound water. In the frozen state were observed a major dispersion (h; 0.14 ns) and a minor one (m; 28 ns), which were ascribed to considerably mobile and less mobile waters. They are similar to but not exactly the same as that for unfreezable water in bovine serum albumin solutions argued by Miura et al. (Biopolymers, 1995, Vol. 36, p. 9). Water is molded into different structures by the triple helix.

Biopolymers↗
PubMed1998

Polysaccharide K induces Mn superoxide dismutase (Mn-SOD) in tumor tissues and inhibits malignant progression of QR-32 tumor cells: possible roles of interferon alpha, tumor necrosis factor alpha and transforming growth factor beta in Mn-SOD induction by polysaccharide K.

Previously we reported the malignant progression of QR-32, a regressor-type tumor clone, following co-implantation with foreign bodies (gelatin sponge or plastic plate) in normal syngeneic C57BL/6 mice. We also reported that the progression of QR-32 cells by a gelatin sponge was significantly inhibited in the mice administered polysaccharide K (PSK) and that PSK induced an increase of radical scavengers, especially manganese superoxide dismutase (Mn-SOD), locally at the site of tumor tissues. In this study, to reveal the possible mechanism by which PSK induced Mn-SOD in the tumor tissues, we examined the mRNA expression and protein levels of inflammatory cytokines in the tissues. We found that mRNAs of tumor necrosis factor alpha (TNFalpha) and interleukin-1alpha (IL-1alpha) were considerably expressed in both PSK-treated and phosphate-buffered-saline-treated tumors, and that the mRNA expression and protein level of interferon gamma (IFNgamma) increased in the tumor tissues treated with PSK. In vitro treatment of QR-32 cells with IFNgamma did not significantly increase the production of Mn-SOD; however, the combination of IFNgamma with TNFalpha increased the Mn-SOD production more effectively than did any of the cytokines used singly. Furthermore, we observed the down-regulation of the mRNA expression and protein level of transforming growth factor beta (TGFbeta) in the tumor tissues treated with PSK, and that in vitro treatment of QR-32 cells with TGFbeta decreased the production of Mn-SOD. These results suggest that PSK suppresses the progression of QR-32 cells by increasing Mn-SOD via the modulation of inflammatory cytokines; that is, by decreasing TGF-beta and increasing IFN-gamma.

Adjuvants, Immunologic↗
PubMed2004

Functional differences in IgG anti-polysaccharide antibodies elicited by immunization of mice with C3d versus ovalbumin conjugates of pneumococcal serotype 14 capsular polysaccharide.

We previously have shown that conjugation of C3d to pneumococcal serotype type 14 capsular polysaccharide (PPS14) significantly enhances anti-PPS14 antibody production to a degree similar to that found when the T-dependent protein carrier ovalbumin (OVA) is coupled to PPS14. However, the anti-PPS14 antibody response to PPS14-C3d conjugates is characterized by less switching from IgM to IgG and lower serum concentrations of anti-PPS14 IgG after secondary immunization. To determine if these quantitative differences in anti-PPS14 IgG are accompanied by qualitative differences in the IgG anti-PPS14 antibodies, we performed several functional assays on serum IgG anti-PPS14 antibodies from mice immunized with PPS14-C3d or PPS14-OVA. Compared with antibodies elicited by immunization with PPS14-C3d, IgG anti-PPS14 antibodies produced after immunization with PPS14-OVA were found to have higher avidity and enhanced function as opsonins. Comparisons of avidity for IgG from serum samples obtained after primary and secondary immunization demonstrated a higher degree of avidity maturation after immunization with PPS14-OVA than with PPS14-C3d. These results suggest that PPS14-C3d conjugates are unlikely to be more efficacious than PPS14 conjugate vaccines incorporating T-dependent protein carriers.

Animals↗
PubMed2003

New structures of the O-specific polysaccharides of Proteus. 3. Polysaccharides containing non-carbohydrate organic acids.

Four new Proteus O-specific polysaccharides were isolated by mild acid degradation from the lipopolysaccharides of P. penneri 28 (1), P. vulgaris O44 (2), P. mirabilis G1 (O3) (3), and P. myxofaciens (4), and their structures were elucidated using NMR spectroscopy and chemical methods. They were found to contain non-carbohydrate organic acids, including ether-linked lactic acid and amide-linked amino acids, and the following structures of the repeating units were established: [Figure: see text], where (S)-Lac and (R)-aLys stand for (S)-1-carboxyethyl (residue of lactic acid) and N(epsilon)-[(R)-1-carboxyethyl]-L-lysine ("alaninolysine"), respectively. The data obtained in this work and earlier serve as the chemical basis for classification of the bacteria Proteus.

Amino Acids↗
PubMed1999

IgG subclasses and avidity of antibodies to polysaccharide antigens in allogeneic BMT recipients after vaccination with pneumococcal polysaccharide and Haemophilus influenzae type b conjugate vaccines.

In a randomized study, 20 adult allogeneic BMT recipients were vaccinated at 6 months and 22 at 18 months after BMT with Haemophilus influenzae type b (Hib)-diphtheria toxoid conjugate vaccine (PRP-D), and 23 recipients at 8 months and 21 at 20 months with pneumococcal polysaccharide (Pnc PS) vaccine. IgG1 and IgG2 subclasses of Pnc PS and Hib antibodies and avidities of Pnc PS IgG antibodies were determined by EIA in sera from patients with at least a two-fold total antibody response to Pnc type 3, 6B, 19F or PRP-D. The Pnc PS vaccine induced predominantly IgG1 Pnc 3 antibody production. Anti-Pnc 6B and 19F responses were mainly IgG2. The time of the Pnc PS vaccination, at 8 or 20 months after BMT, did not influence the IgG subclass response pattern. The PRP-D vaccine induced predominantly IgG2 anti-Hib production in the patients vaccinated at 6 months after BMT. The patients vaccinated at 18 months produced IgG1 and IgG2 antibodies more evenly. The same patient was able to produce predominantly IgG1 subclass antibodies to one antigen, Pnc 3, 6B, 19F or Hib, and IgG2 antibodies to another. The avidities of anti-Pnc 6B and 19F 1 month after vaccination were similar to those before vaccination, anti-Pnc 3 avidity was lower than before vaccination but matured in 15 months. The IgG subclass distribution and avidity were similar in the patients with and without chronic GVHD. In conclusion, the IgG response to Pnc type 3 was predominantly IgG1 as in infants and IgG2 to PRP-D, Pnc 6B, and 19F as in adults. Early vaccination after BMT or the presence of chronic GVHD did not impair the quality of response to Pnc PS and PRP-D vaccines.

Adolescent↗
PubMed2003

The Edwardsiella ictaluri O polysaccharide biosynthesis gene cluster and the role of O polysaccharide in resistance to normal catfish serum and catfish neutrophils.

Edwardsiella ictaluri, the causative agent of enteric septicaemia of catfish (ESC), expresses long O polysaccharide (OPS) chains on its surface. The authors previously reported the construction of an isogenic Ed. ictaluri OPS mutant strain and demonstrated that this strain is avirulent in channel catfish. This paper reports the cloning of the Ed. ictaluri OPS biosynthesis gene cluster and identification of the mutated gene in the OPS-negative strain. The sequenced region contains eight complete ORFs and one incomplete ORF encoding LPS biosynthesis enzymes. The mutated gene (designated wbiT) was similar to other bacterial galactose-4-epimerases. Glycosyl composition analysis indicated that wild-type Ed. ictaluri OPS contains higher amounts of galactose and N-acetylgalactosamine than the OPS mutant strain, which correlated well with predicted functions of the genes identified in the OPS biosynthesis cluster. The OPS mutant had a relatively small, but significant, decrease in its ability to survive in normal catfish serum compared to wild-type Ed. ictaluri, but it retained the ability to resist killing by catfish neutrophils.

Animals↗
PubMed1999

Pneumococcal capsular polysaccharide preparations may contain non-C-polysaccharide contaminants that are immunogenic.

We measured the capacity to opsonize Streptococcus pneumoniae serotype 6B and estimated the concentration of immunoglobulin G anti-6B capsular polysaccharide (PS) antibodies in 25 pre- and postimmune sera from adults immunized with a pneumococcal PS vaccine. We first studied two postvaccination serum samples displaying less opsonophagocytic capacity than expected. The majority of anti-6B antibodies in the two samples reacted with the capsular PSs of several unrelated serotypes (2, 4, 9V, 19F, and 23F) and with the lysate of noncapsulated S. pneumoniae bacteria but not with C-PS. The non-type-specific antibodies accounted for at least one-half of anti-6B antibodies in 40% of prevaccination sera and 10% of postvaccination sera from adults. The non-type-specific antibodies could be demonstrated in the enzyme-linked immunosorbent assays (ELISAs) for pneumococcal antibodies to other serotypes (4, 9V, 18C, 19F, and 23F). The nonspecific antibodies appear to bind a contaminant(s) in the current preparations of capsular PS. ELISA for antibodies to pneumococcal capsules may not be serotype specific for some samples.

Adult↗
PubMed1998

Streptococcus pneumoniae type 14 polysaccharide-conjugate vaccines: length stabilization of opsonophagocytic conformational polysaccharide epitopes.

A simple and convenient method was developed for the preparation of Streptococcus pneumoniae type 14 polysaccharide (Pn14PS)-tetanus toxoid (TT) conjugate vaccines, using terminally linked Pn14PS fragments of different lengths. Native Pn14PS was simultaneously depolymerized and activated for conjugation by partial N-deacetylation followed by nitrous acid deamination which yielded fragments (1.4 to 150.0 kDa) having a free aldehyde at the reducing end. These were then conjugated to TT through their terminal aldehydic groups, using the reductive amination procedure. All of the above conjugates, when injected in rabbits, induced anti-Pn14PS antibodies, whereas the native Pn14PS did not. The amounts of anti-Pn14PS antibodies elicited by these conjugates, as determined by enzyme-linked immunosorbent assay, followed a trend with conjugates containing the highest-molecular-weight Pn14PS eliciting the highest titers. The same trend was also observed in the ability of the antibodies to opsonize and kill live type 14 pneumococci, although the increase in opsonophagocytic activity was more pronounced and did not correlate linearly with increases in antibody titer. Competitive inhibition of the binding of different conjugate antisera to the native Pn14PS, using Pn14PS fragments as inhibitors, established that the conjugates induced antibodies with specificities for different lengths of Pn14PS beginning at 2 repeating units (RU). It was also established, both immunologically and antigenically, that at least 4 RU of Pn14PS were required to form an extended conformational epitope and that approximately 22 RU of Pn14PS were required to duplicate the same epitope on the same saccharide chain. The conformational epitope was found to be essential for the induction of antibodies with high opsonophagocytic activity and that augmentation of opsonophagocytic activity was also dependent on further chain extension.

Animals↗
PubMed1990

[Antigenic polysaccharides of bacteria. 37. Structure of the polysaccharide chain of Pseudomonas syringae pv.tabaci (serogroup VII) lipopolysaccharide].

The structure of the O-specific polysaccharide chain of Pseudomonas syringae pv. tabaci strain 223 (serogroup VII) lipopolysaccharide was established on the basis of one- and two-dimensional 1H NMR analysis, 13C NMR analysis and calculation of optical rotation. The structure determined by the non-destructive way was confirmed by acid hydrolysis and methylation. (Sequence: see text). O-Antigen of the strain studied is similar in structure and serological properties to O-antigens of Pseudomonas syringae strains belonging to serogroup I.

Antigens, Bacterial↗
PubMed1988

Functional activities of human antibody induced by the capsular polysaccharide or polysaccharide-conjugate vaccines against Haemophilus influenzae type b.

To determine the in vitro and in vivo activity of human antibody induced by different Haemophilus influenzae type b (Hib) vaccines, pooled human antisera obtained from adults immunized with either polyribosyl ribitol phosphate (PRP) or PRP-conjugated with diphtheria toxoid (PRP-D) vaccines were evaluated for opsonic and protective activity against Hib. In vitro, opsonophagocytic studies revealed that PRP-D induced antisera were approximately 2.5-fold more effective than PRP-induced antisera in supporting neutrophil-mediated killing of an Hib strain. In vivo studies using the infant rat model or Hib disease revealed that the decay of PRP antibody was similar with PRP or PRP-D induced antisera in unchallenged rats. However, in infant rats challenged with Hib, the PRP induced antibody decayed more rapidly than the PRP-D induced antibody as shown by significantly shorter half-life of the former. The protective efficacy was significantly greater with the PRP-D induced antisera than with the PRP induced antisera. This finding was shown by the significantly lower incidence of bacteraemia and the 5-fold lower dose of antibody required for 50% protection against bacteraemia in rats receiving the PRP-D induced antisera. The findings suggest that antibody to PRP induced by PRP-D vaccine is more opsonic and protective against Hib, and also decays more slowly in infant rats challenged with Hib than does antibody induced by PRP vaccine. Further studies are needed to elucidate the reason(s) for this difference in functional activity and in half-life of PRP antibody induced by PRP or by PRP-D vaccines.

Adult↗