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PubMed1979

Complex of meningococcal group B polysaccharide and type 2 outer membrane protein immunogenic in man.

A noncovalent complex of meningococcal group B polysaccharide and type 2 outer membrane protein has been characterized and its potential as a vaccine against group B meningococcal disease investigated. The polysaccharide component was found to have a partition coefficient, K(d), of 0.34 on Sepharose CL-4B in the presence of sodium deoxycholate. The protein consisted of four to five major proteins including the principal outer membrane protein. Hydrophobic binding between the protein and polysaccharide was demonstrated by gel filtration and isopycnic CsCl density gradient centrifugation and found to involve all of the proteins. After demonstrating safety and immunogenicity in animals, two lots of vaccine were tested in a total of eight volunteers. Two 120-mug doses were given subcutaneously at 0 and 5 wk. Mild local reactions occurred in all eight volunteers, but no systemic reactions were observed. 2 wk after the first dose, six of the volunteers had increased levels of bactericidal antibodies against both the group B polysaccharide and the outer membrane proteins. Antibody rises to the group B polysaccharide (mean 6-fold) were confirmed by passive hemagglutination assays and rises to the proteins (mean 10-fold) by a solid phase radioimmunoassay. The second dose resulted in little or no increase in antibody titers. Antibody titers declined over a period of 14 wk but mostly remained above preimmunization levels. Bactericidal antibodies with specificity for the group B polysaccharide were mostly of the immunoglobulin (Ig)M class, and were directed against a determinant associated only with high molecular weight polysaccharides. We conclude that both the group B polysaccharide and the outer membrane protein are immunogenic in man when presented as a complex and that the complex warrants further testing and development as a vaccine against group B meningococcal disease.

Adult↗
PubMed1994

Maternal immunization of mice with group B streptococcal type III polysaccharide-beta C protein conjugate elicits protective antibody to multiple serotypes.

Group B streptococcal infection is a major cause of neonatal mortality. Antibody to the capsular polysaccharide protects against invasive neonatal disease, but immunization with capsular polysaccharides fails to elicit protective antibody in many recipients. Conjugation of the polysaccharide to tetanus toxoid has been shown to increase immune response to the polysaccharide. In animal models, C proteins of group B streptococci are also protective determinants. We examined the ability of the beta C protein to serve in the dual role of carrier for the polysaccharide and protective immunogen. Type III polysaccharide was covalently coupled to beta C protein by reductive amination. Immunization of rabbits with the polysaccharide-protein conjugate elicited high titers of antibody to both components, and the serum induced opsonophagocytic killing of type III, Ia/C, and Ib/C strains of group B streptococci. Female mice were immunized with the conjugate vaccine and then bred; 93% of neonatal pups born to these dams vaccinated with conjugate survived type III group B streptococcal challenge and 76% survived type Ia/C challenge, compared with 3% and 8% survival, respectively, in controls (P < 0.001). The beta C protein acted as an effective carrier for the type III polysaccharide while simultaneously induced protective immunity against beta C protein--containing strains of group B streptococci.

Animals↗
PubMed1983

Screening of host-mediated antitumor polysaccharides by crossed immunoelectrophoresis using fresh human serum.

On crossed immunoelectrophoresis, human serum C3 (the third component of complement) converted by antitumor polysaccharides (ATSO [antitumor polysaccharide oral], AB-P [Agaricaus blazei polysaccharide], GU-P [Grifora umbellata polysaccharide], PS-K [polysaccharide Kureha] and zymosan) moved faster than native C3, appearing as the 3rd peak. The ratio of height of the 3rd peak to the alpha 2-macroglobulin (alpha 2-M) peak was linearly proportional to the dose of ATSO. At the dose of 500 micrograms/ml antitumor polysaccharides, the ratios were higher than 0.76, and the ratios for the serum treated with polysaccharide of no antitumor activity (dextran and gum arabic) were less than about 0.52. This ratio readily determined in vivo can be used as a measure for the antitumor activity of polysaccharides.

Animals↗
PubMed2003

Recent trends in the use of polysaccharides for improved delivery of therapeutic agents: pharmacokinetic and pharmacodynamic perspectives.

New and innovative methods of delivery of therapeutic agents using polysaccharides have been recently developed, which target site of action, increase the intensity and/or prolong pharmacologic action, and/or reduce toxicity of small molecule drugs, proteins, or enzymes. This review is focused on the role of dextran, pullulan, and mannan polysaccharides in such applications. While dextran and pullulan are glucose polymers with different glucosidic linkages, mannan is composed of mannose units. In terms of pharmacokinetics of the carriers themselves, molecular weight (MW), electric charge, various chemical modifications, and degree of polydispersity and/or branching would mostly determine their fate in vivo. Generally, large MW polysaccharides (MWs > or = 40 kD) have low clearance and relatively long plasma half life, resulting in accumulation in reticuloendothelial or tumor tissues. The tumor accumulation in most cases is a passive targeting due to "enhanced permeation and retention" of macromolecules by tumors. Additionally, drugs such as anticancer agents may be actively targeted to specific cells by polysaccharides to which appropriate ligands are attached. In terms of mode of use, polysaccharides have been utilized in a variety of innovative ways for improvement of drug delivery. Their most important application has been as carriers for preparation of macromolecular prodrugs that are normally inactive and need to release the active drug at the site(s) of interest. Also, they have been used for preparation of macromolecule-protein conjugates, which may retain the activity of the proteins, in order to increase the duration of effect and decrease the immunogenicity of proteins. Several other new applications, such as polysaccharide-anchored liposomal formulations, have also been gained attention recently and are briefly reviewed here. Finally, four recent examples of polysaccharide-based delivery systems involving specific drugs/imaging agents are reviewed in detail in terms of their development, pharmacokinetics, and pharmacodynamics. Collectively, these data suggest that macromolecular polysaccharides are promising agents for improving drug delivery.

Animals↗
PubMed2006

Differential regulation of protein- and polysaccharide-specific Ig isotype production in vivo in response to intact Streptococcus pneumoniae.

Adaptive humoral immunity to extracellular bacteria is largely mediated by antibody specific for both protein and polysaccharide antigens. Proteins and polysaccharides are biochemically distinct, and as a result are processed differently by the immune system, leading to different mechanistic pathways for eventual elicitation of specific Ig isotypes. Much of our current knowledge concerning the parameters underlying anti-protein and anti-polysaccharide Ig responses have come from studies using soluble, purified antigens. However, the lessons learned from these studies are not entirely applicable to the mechanisms underlying physiologic anti-protein and anti-polysaccharide Ig responses to intact bacteria. Specifically, unlike isolated, soluble antigens, intact bacteria are complex particulate immunogens in which multiple protein and polysaccharide antigens, and bacterial adjuvants (e.g. Toll-like receptor ligands) are co-expressed, indeed often physically linked. In this review, data from a series of recent studies are discussed in which heat-killed, intact Streptococcus pneumoniae was used as an immunogen to study the mechanisms underlying in vivo anti-protein and anti-polysaccharide Ig isotype induction. An unexpected role for CD4(+) T cells and dendritic cells for induction of IgG anti-polysaccharide responses by intact bacteria is discussed, and shown to have distinct mechanistic features from those that mediate anti-protein responses. The further role of cytokines, Toll-like receptors, and B cell receptor signaling in mediating these responses, and its implications for the effectiveness of anti-pneumococcal, polysaccharide-based vaccines, is also discussed.

Animals↗
PubMed2003

[Gravity resistance, another graviresponse in plants--function of anti-gravitational polysaccharides].

The involvement of anti-gravitational polysaccharides in gravity resistance, one of two major gravity responses in plants, was discussed. In dicotyledons, xyloglucans are the only cell wall polysaccharides, whose level, molecular size, and metabolic turnover were modified under both hypergravity and microgravity conditions, suggesting that xyloglucans act as anti-gravitational polysaccharides. In monocotyledonous Poaceae, (1-->3),(1-->4)-beta glucans, instead of xyloglucans, were shown to play a role as anti-gravitational polysaccharides. These polysaccharides are also involved in plant responses to other environmental factors, such as light and temperature, and to some phytohormones, such as auxin and ethylene. Thus, the type of anti-gravitational polysaccharides is different between dicotyledons and Poaceae, but such polysaccharides are universally involved in plant responses to environmental and hormonal signals. In gravity resistance, the gravity signal may be received by the plasma membrane mechanoreceptors, transformed and transduced within each cell, and then may modify the processes of synthesis and secretion of the anti-gravitational polysaccharides and the cell wall enzymes responsible for their degradation, as well as the apoplastic pH, leading to the cell wall reinforcement. A series of events inducing gravity resistance are quite independent of those leading to gravitropism.

Cell Wall↗
PubMed2000

[The isolation, preliminary study of structure and physiological activity of water-soluble polysaccharides from squeezed berries of Snowball tree Viburnum opulus].

Water-soluble polysaccharide fractions VO1-VO4 were isolated from the squeezed berries of snowball tree (Viburnum opulus) by successive extraction with water at various temperatures and pH and with aqueous solutions of ammonium oxalate. These fractions were purified by ion-exchange chromatography on DEAE cellulose, and the homogeneity of the purified polysaccharides was determined by gel filtration on Sephacryl S-500. Acidic polysaccharides close to pectins in their sugar composition were found in all the extracts (fractions VO1-1, VO2-1, VO3-2, and VO4-2). Residues of galacturonic acid, galactose, arabinose, and (to a lesser extent) rhamnose are their main constituents. Neutral polysaccharides composed mainly of galactose and mannose residues were additionally found in fractions extracted with acidified water (pH 4.0) and with aqueous ammonium oxalate solutions. Partial acidic hydrolysis and digestion with pectinase of acidic polysaccharides indicated that their carbohydrate backbone consists of alpha-1,4-linked residues of D-galacturonic acid. NMR spectra of acidic polysaccharides (fractions VO3-2 and VO3-3) confirmed this and demonstrated that their side oligosaccharide chains are composed of beta-1,4-linked galactopyranose residues and of terminal and 2,5- and 3,5-substituted residues of alpha-arabinofuranose at a Gal: Ara ratio of 3:1. Some polysaccharides from V. opulus were found to possess an immunostimulating activity: they enhance phagocytosis, in particular, the phagocytic index and the secretion of lysosomal enzymes with peritoneal macrophages. Calcium ions were found to be necessary for the appearance of the stimulating effect of acidic polysaccharides from V. opulus.

Adjuvants, Immunologic↗
PubMedDate not supplied

Potential of polysaccharide anchored liposomes in drug delivery, targeting and immunization.

PURPOSE: Recently the emphasis has been laid upon the carbohydrate mediated liposomal interactions with the target cells. Among the various carbohydrate ligands, such as glycoproteins, glycolipids, viral proteins, polysaccharides, lipo-polysaccharides and other oligosaccharides, this review deals with the polysaccharide anchored liposomal system for their potential in drug delivery, targeting and immunization. Over the years, various strategies have been developed which include coating of the liposomal surface with natural or hydrophobized polysaccharides, namely mannan, pullulan, amylopectin, dextran etc., or their palmitoyl or cholesteroyl derivatives. The polysaccharide(s) coat tends vesicular constructs physicochemically stable in bio-environments and site-specific. The aim of improving the physical and biochemical stability of liposomes and the ability to target liposomes to specific organs and cells, were the major attributes of the polysaccharide anchored liposomes. In this review the authors attempted to overview various applications of polysaccharide bearing liposomes, including lung therapeutics, targeted chemotherapy, cellular targeting, cellular or mucosal immunity and macrophage activation. Future prospects of the delivery module are also discussed. The review in general explores the concepts, options and opportunities of polysaccharide anchored liposomes with newer perspectives.

Administration, Oral↗
PubMed1975

Isolation and characterization of a bacteriophage polysaccharide.

A high molecular weight heteropolysaccharide, composed of glucose, glucuronic acid, N-acetylglucosamine, and mannose in an approximate molar ratio of 1:2:2:5, respectively, was isolated from phage K-2 and from the soluble fraction of phage-infected Aerobacter aerogenes lysates. Treatment of pure phage with 8 M urea at 4 degrees quantitatively solubilizes the bound polysaccharide and capsular polysaccharide (Yurewicz, E.C., Ghalambor, M.A., Duckworth, D.H., and Heath, E.C. (1971) J. Biol. Chem. 246, 5607-5616) with the release of only traces of other phage constituents; on this basis, it was concluded that the polysaccharide, like the the glycanohydrolase, is externally localized in the phage structure. Phage polysaccharide and glycanohydrolase fractionate similarly on ion exchange resins and gel electrophoresis in sodium dodecyl sulfate, but each may be purified to homogeneity by the procedures employed. The biosynthesis of the polysaccharide was shown to be uniquely dependent upon phage K-2 infection by: (a) absence of the polysaccharide in cells, the culture filtrate, or sonicated extracts of uninfected cells; (b) kinetics of polysaccharide synthesis following phage infection; and (c) isotopic double-labeling experiments that demonstrated the synthesis of polysaccharide only after initiation of phage replication in infected cells.

Acetylglucosamine↗
PubMed2004

[Food allergy: effect of proteins-lipids and proteins-polysaccharides interactions].

The most widely used ingredients in food formulation are proteins, lipids and polysaccharides. Proteins-lipids and proteins-polysaccharides interactions play a key role in the structure, stability, sensorial and nutritional properties of formulated foods. The objective of the present study is to highlight the importance of proteins-lipids and proteins-polysaccharides interactions, on the immuno-reactivity of allergenic proteins. Two models have been studied, on the one hand refined and not refined oils (soya and sunflower) and soya lecithin, on the other hand mixtures based on peanut proteins and polysaccharides (arabic gum, pectin, xylan). STUDY OF OILS: We have extracted proteins, using a PBS buffer, from refined and not refined oils from soya, sunflower and from soya lecithin, determined protein concentrations and identified allergenic proteins using SDS-PAGE electrophoresis and immuno-blotting. Phospholipids are determined by atomic absorption spectrometry. The protein determination and SDS-PAGE show the presence of a higher amount of proteins in not refined oils and lecithin as compared to refined oils. An important amount of proteins associated to phospholipids are eliminated by degumming on the form of lecithin. On the other hand, residual proteins from refined oils are accompanied by phospholipids. Immuno-blots reveal the presence of a 56 kDa allergen in oils issued from soya seeds and soya lecithin, and the presence of a 67 kDa allergen in oils issued from sunflower seeds. We conclude that the presence or elimination of proteins, especially allergens from oils is linked to amphiphilic association to phospholipids. STUDY OF PEANUT PROTEINS-POLYSACCHARIDES MIXTURES: We have digested in vitro proteins in a dialysis bag using a multi-enzymatic method and characterized proteins and peptides using SDS-PAGE electrophoresis and immuno-blotting. Our results confirm that peanut proteins alone are digested by proteases and that a number of large peptides still have epitopes recognized by anti-peanut proteins antibodies. Our results also show that the presence of polysaccharides changes the peptidic profile after digestion and that, depending on the polysaccharide type, smaller or larger peptides can be obtained in the dialysis bag. Smaller peptides are obtained using pectin whereas larger peptides are obtained using arabic gum and xylan. In the latter case, an increasing amount of peptides reacts to antibodies. Our first observations clearly show the need to better understand modifications of proteins allergenicity induced by the presence of other ingredients such as polysaccharides and lipids, in relation to technological treatments.

Allergens↗
PubMed2006

[Study on the mustard of polysaccharides].

The objective of this study is to isolate and purify the polysaccharides fractions from mustard and to determine the constituent characters. Hot water extracting and ethanol precipitating method were employed to isolate polysaccharides. After the removal of protein by Sevag method, the purified mustard polysaccharides were dried by frozen drier. The amount of total carbohydrates of mustard polysaccharides was measured with phenol-sulfuric acid method. IR spectrometry, UV-spectrophotometer, and automatic spectropolarimeter were used to determine the characteristic absorption and optical rotation of the polysaccharides, respectively. Size exclusion chromatography with laser light scattering technology was employed to measure the molecular masses. The monosaccharides contained in the mustard polysaccharides were analysed by HPLC. The amount of total carbohydrates in mustard polysaccharides is 98.96%. The molecular weight distribution was 1.42 x 10(4)-2.55 x 10(6), and eighty percent was distributed in 2.1 x 10(5). The monosaccharide constituent of mustard polysaccharides were glucose, fructose, arabinose, galactose and xylose, and their molar proportions are 21.4 : 12.89 : 5.6 : 4.1 : 2.5, respectively.

Molecular Weight↗
PubMed1991

Impaired polysaccharide responses in immunodeficient patients: relevance to bone marrow transplant patients.

Bone marrow transplant patients are at increased risk for pneumococcal and H. influenzae type b (HIB) infections. These polysaccharide encapsulated bacteria are also pathogens for young healthy children. In healthy children age related susceptibility has been associated with poor response to polysaccharides and low serum IgG2 subclass antibody concentrations. Of note, immune reconstitution following bone marrow transplantation has been characterized by slow return of both the response to polysaccharides and IgG2 serum concentrations. Thus immune reconstitution following bone marrow transplantation is similar to the maturation that occurs in healthy children. In addition to transplant patients, we have identified five groups of immunodeficient patients who are at increased risk for polysaccharide encapsulated pathogens. IgG2 subclass deficient patients were shown to have impaired responses to polysaccharide antigens. We have also defined "Selective Antibody Deficiencies" which are individuals with normal IgG subclass concentrations but poor responses to polysaccharide antigens. Next, patients who developed HIB disease in spite of immunization (i.e. HIB vaccine failures) were demonstrated to have lower serum IgG2 and IgG4 subclass concentrations compared to controls. Finally, Native Americans (an ethnic group with an increased incidence of pneumococcal and HIB infections) were shown to be poor responders to polysaccharide antigens and have significantly lower concentrations of serum IgG2 and IgG4 as compared to controls. New HIB polysaccharide vaccines linked to protein antigens (conjugate vaccines) have been developed that are more immunogenic in healthy young children. In addition, these conjugate vaccines have resulted in protective responses in each of the newly described immunodeficient groups. We therefore now propose to evaluate bone marrow transplant patients' response to HIB conjugate vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Bacterial↗
PubMed1991

Structural determination and immunochemical characterization of the type V group B Streptococcus capsular polysaccharide.

The type V capsular polysaccharide of group B Streptococcus has been isolated and purified, and its repeating unit structure determined. The native type V polysaccharide contains D-glucose, D-galactose, 2-acetamido-2-deoxy-D-glucose, and sialic acid in a molar ratio of 3:2:1:1. Methylation analysis and 1H NMR and 13C NMR analysis of the native type V polysaccharide and of its specifically degraded products permitted the determination of the repeating unit structure of the type V polysaccharide: [formula: see text] The type V polysaccharide has certain structural features in common with other group B streptococcal capsular polysaccharides but is antigenically distinct: no immunologic cross-reactivity was observed between type V and types Ia, Ib, II, III, or IV polysaccharides. Studies of antibody binding to the partially degraded forms of the type V polysaccharide indicated that the native epitope is complex, involving most if not all of the sugar residues of the repeating unit.

Bacterial Capsules↗
PubMed1990

Human polysaccharide-specific B cells are responsive to pokeweed mitogen and IL-6.

The responsiveness of polysaccharide-specific B cells to PWM was examined in vitro. Spleen cells from six patients immunized with Haemophilus influenzae type b-diphtheria toxoid, pneumococcal and meningococcal vaccines were T cell-depleted and separated by Percoll density gradient centrifugation. In each B cell fraction, spontaneous antibody production was demonstrated to capsular polysaccharides as well as diphtheria toxoid. The peak of spontaneous antibody production was demonstrated to be five to seven days after immunization. When T cells and PWM were added, the total Ig secretion increased in all B cell fractions. PWM also enhanced IgG antibody directed to each of three polysaccharide Ag measured. This enhancement was most noticeable for nonresting B cells. The PWM effect was not confined to IgG, as IgM and IgA to Neisseria meningitidis type C were measured and also enhanced. The kinetics of the PWM response demonstrated the most IgG antibody to polysaccharide Ag from spleens immunized five to seven days before splenectomy. When the patients were immunized either 2 days or 4 mo before splenectomy, no spontaneous IgG antibody to polysaccharides was detected although PWM induced small amounts of antibody. Finally, anti-IL-6 antibody blocked PWM-induced total and polysaccharide-specific antibody production. We conclude that human polysaccharide-specific B cells are responsive to PWM and IL-6. We suggest that polysaccharide B cells are not truly "T cell-independent" and may respond to T cell lymphokines and thus are similar to protein-specific B cells.

Antibodies, Bacterial↗
PubMed1986

Cell surface receptors for sulphated polysaccharides: a potential marker for macrophage subsets.

The expression of a diverse array of receptors for sulphated polysaccharides on lymphocytes has been demonstrated by Parish & Snowden (1985). This paper presents evidence to suggest that other cell types, namely macrophages, polymorphonuclear leucocytes, mast cells and fibroblasts, can bind similar polysaccharides. Using a rosetting assay and eleven structurally unique polysaccharides, each cell type was observed to bind a characteristic array of these polysaccharides. Analysis of the polysaccharide reactivity of macrophages revealed that BCG-activated and thioglycollate-elicited macrophages express an expanded repertoire of reactivity compared to resident peritoneal macrophages. For example, only thioglycollate-elicited macrophages, but not resident and BCG-activated peritoneal macrophages, reacted with the glycosaminoglycans, chondroitin-4-sulphate, chondroitin-6-sulphate and dermatan sulphate, while both BCG- and thioglycolate-activated, but not resident peritoneal macrophages, bound pentosan polysulphate-coupled sheep erythrocytes. The expression of the receptors for chondroitin-4 and -6-sulphate was observed to be cyclic and peaked at 2 and 5-6 days after thioglycollate treatment. Preliminary analyses of the functional significance of the observed binding of polysaccharides to macrophages revealed that heparin, fucoidan and kappa-carrageenen were specifically endocytosed. However, endocytosis of all other test polysaccharides was not observed. Finally, polysaccharide-coupled sheep erythrocytes were not phagocytosed, even though they interacted strongly with the macrophage surface. The possible relevance of these observations to an inflammatory response and as a means of identifying cellular subsets is discussed.

Animals↗
PubMed1986

Analytical, toxicological and immunological consequences of the use of N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide as coupling reagent for the preparation of meningococcal group C polysaccharide-tetanus toxoid conjugate as vaccine for human use.

For the preparation of meningococcal group C polysaccharide-tetanus toxoid conjugate the reactive reagent N-ethyl-N'-(dimethylaminopropyl) carbodiimide is used. The application of this reagent results in a number of stable linkages (viz. "peptide" linkages between the polysaccharide and tetanus toxoid, intrachain ester linkages in the polysaccharide component and binding of the N-acylurea derivative of the reagent) and less stable ones (viz. anhydride linkages). As a consequence of the reaction, the reagent is converted to a non-reactive urea derivative. The toxic properties of the reagent and of the converted reagent were studied. These properties do not contraindicate the use of the coupling reagent for the preparation of vaccines for human use. In addition analytical methods have been developed for the quantitative evaluation of the coupling reagent, the reaction products and for the N-acylurea derivative of the reagent and of the residual reactivity of conjugates for primary aminogroups. Although no test was performed for the assay of ester linkages in the polysaccharide component of the conjugate, evidence is presented that such linkages may be present. The results of the test for residual reactivity indicated a spontaneous rearrangement of linkages after the preparation of the conjugate. In addition the influence of the ratio of coupling reagent-to-polysaccharide and tetanus toxoid on antigenic and immunogenic activities of the conjugate was studied. An increase of the ratio resulted in a decrease of the antigenic activity of the polysaccharide component but in an increase of its immunogenic activity as to the induction of IgG antibodies to the polysaccharide. The immunogenic activity of the polysaccharide component correlated rather well with the antigenic activity measured in heterologous enzyme-linked immunosorbent assay using antibodies to both components.

Antigens, Bacterial↗
PubMed1978

Pneumococcal polysaccharide immunization in infants and children.

By using indirect hemagglutination, the antibody responses of normal infants and children to an octavalent pneumococcal vaccine that contained pneumococcal polysaccharide types 1, 3, 6, 7, 14, 18, 19, and 23 were evaluated. By 2 years of age, there was a significant rise in hemagglutination titers to all the polysaccharide types, except type 19. By 6 to 8 months of age, five of the eight types of pneumococcal polysaccharides tested resulted in up to 60% responders and, by 2 years, a significant number responded to all pneumococcal polysaccharide types in the vaccine. Pneumococcal polysaccharide type 3 resulted in a significant antibody response as early as 3 months of age, whereas type 19 never resulted in a significant antibody response. Except for type 3, it seemed that when the other pneumococcal polysaccharides tested produced an antibody response, the degree of resonse did not subsequently change significantly with increasing age. The relationship of antibody response to age for pneumococcal polysaccharides is similar to that found for other polysaccharide vaccines. Based on the results of our study, we would recommend immunization with pneumococcal vaccine at 6 months of age with repeat immunization at 2 years of age, especially in high-risk children.

Age Factors↗
PubMed1977

Optical polarization reveals different ultrastructural molecular arrangement of polysaccharides in the yeast cell walls.

The topo-optical aldehyde bisulfite-toluidine blue (ABT) reaction of vicinal OH and amino-OH groups offers new ways to study the ultrastructure of polysaccharides in different biological substrates. Through oriented dye binding on the reacting groups, the ABT reaction induces strong birefringence on the linearly ordered polysaccharides, which is negative with respect to their chain length. Using this method, two types of molecular order of the polysaccharides could be distinguished in the cell walls and capsules of yeasts. (1) The optically negative spherulitic character of the yeasts after the ABT reaction indicated that the toluidine blue molecules were bound tangentially (in a surface-parallel pattern) while the polysaccharide chains of the cell walls and capsules were oriented mainly radially. This structural pattern may be explained as resulting from a helicoid conformation of the polysaccharide component. (2) Acid or alkali hydrolysis removed the radially oriented polysaccharide component of the cell wall. The remaining, resistant polysaccharides showed up in the form of optically positive spherulites indicating radially oriented dye molecules on a circularly ordered, micellar polysaccharide texture.

Candida albicans↗