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PubMed1952

Group A streptococcus polysaccharide: studies on its preparation, chemical composition, and cellular localization after intravenous injection into mice.

A method was developed for the extraction of the group A streptococcus polysaccharide employing pepsin digestion of ground streptococcal cells. This method did not result in the isolation of polysaccharide with chemical and physical chemical properties different from those exhibited by preparations extracted with hot formamide. Studies of the chemical composition of this polysaccharide demonstrated it to be composed chiefly of rhamnose and glucosamine monosaccharide units in the approximate ratio of five moles of rhamnose to two moles of glucosamine. The fate of the polysaccharide after intravenous injection into mice was studied using the fluorescent antibody technique. It was found to be rapidly eliminated by the kidney. The presence of the polysaccharide in the renal tubular epithelial cells during the excretory phase was the only evidence of its cellular localization that could be detected under the conditions of these experiments.

Animals↗
PubMed1999

Pneumococcal conjugate vaccine primes for polysaccharide-inducible IgG2 antibody response in children with recurrent otitis media acuta.

Children with frequent recurrent episodes of otitis media may have a deficient IgG2 antibody response to polysaccharide antigens. Five otitis-prone children were vaccinated with heptavalent pneumococcal conjugate vaccine. While all had an IgG1 antibody response to all pneumococcal serotypes included in the conjugate vaccine, the IgG2 response, especially to serotypes 6B, 9V, 19F, and 23F, was poor. However, vaccination with a 23-valent polysaccharide vaccine 6 months after conjugate vaccination induced an 11.5- to 163-fold increase in IgG2 anti-polysaccharide antibody titers. Thus, an IgG2 polysaccharide antibody deficiency can be overcome by priming with a pneumococcal conjugate vaccine followed by a booster with a polyvalent polysaccharide vaccine.

Antibodies, Bacterial↗
PubMed2002

Bioactive polysaccharides from traditional Chinese medicine herbs as anticancer adjuvants.

PURPOSE OF STUDY: To review the nature, extent, bioactivities, and clinical application of polysaccharides in Traditional Chinese Medicine (TCM) especially as adjuvants in cancer treatment. METHODOLOGY: Literature review. FINDINGS: Many fungal- and plant-derived bioactive polysaccharides with a broad range of immunomodulatory activities are found in TCM. Some such polysaccharides have been developed into drugs and show clinical efficacy in controlled trials while the majority of such compounds remain as nutraceuticals with only preliminary research. Such polysaccharides are generally nontoxic and possess other bioactivities such as inducing differentiation, stimulating hematopoiesis, antimetastasis, and antiangiogenesis, which make them ideal adjuvants in modern cancer therapy. CONCLUSION: Bioactive polysaccharides occur extensively in TCM herbs and are the basis of potentially useful application of TCM as an adjuvant in cancer therapies.

Adjuvants, Immunologic↗
PubMed1992

Bactericidal activity of two IgG2a murine monoclonal antibodies with distinct fine specificities for group B Neisseria meningitidis capsular polysaccharide.

To analyze the fine specificity of the protective IgG response for the capsule of group B Neisseria meningitidis (Men B) induced after immunization with live bacteria, two specific IgG2a monoclonal antibodies (mAb) have been generated from hyperimmunized Balb/c and NZB mice (101C11 and 30H12). They specifically recognize in direct and competitive binding assays the capsular polysaccharides of Men B and Escherichia coli k1 on condition that the length of the polysaccharidic chain is sufficient to make a conformational structure (more than 15 monomers of alpha (2-->8) linked N-acetyl neuraminic acid). They do not interact with group A and group C Neisseria meningitidis polysaccharides in ELISA. A chemical derivative of the Men B polysaccharide, the N-propionylated Men B polysaccharide, considered as mimicking a unique bactericidal epitope on the surface of Men B is recognized by 101C11 but not by 30H12. The two mAb have, in vitro, a specific bactericidal activity against live Men B which do not seem serotype specific. Moreover, the killing of Men B mediated by 30H12 can be neutralized by an anti-idiotypic mAb (216F11) generated from A/J mice, immunized with polymerized 30H12. These data show that at least two distinct bactericidal epitopes exist on the surface of the Men B capsule.

Animals↗
PubMed1987

Interferon induction by endotoxin-derived nontoxic polysaccharides.

Polysaccharide-rich preparations from Serratia marcescens-derived endotoxin and components thereof, including Lipid A, were studied in terms of their ability to induce interferon (IFN) activity in murine spleen cell cultures in vitro. Although the polysaccharide-rich derivatives, similar to intact endotoxin, were only weak stimulators for IFN induction, pretreatment of splenocyte cultures with recombinant interleukin-2 (IL-2) significantly increased IFN-inducing activity. Both an endotoxin-derived polysaccharide and a "White type" polysaccharide prepared from intact Serratia had similar ability to induce IFN in vitro, but only when spleen cells were first treated with IL-2. The polysaccharide preparations were nontoxic as compared with the high degree of toxicity of the intact endotoxin, yet induced similar IFN levels as whole endotoxin. Much of the IFN induced by these preparations was of the gamma type, since activity was either not neutralized or only incompletely neutralized by treatment with anti-alpha/beta interferon antibody.

Animals↗
PubMed1983

Effects of soy polysaccharide on gastrointestinal functions, nutrient balance, steroid excretions, glucose tolerance, serum lipids, and other parameters in humans.

A diet-controlled study with a cross-over design was conducted to determine the effect of soy polysaccharide on gastrointestinal functions, nutrient balance, steroid excretion, blood lipid levels, postprandial serum glucose response, and other blood parameters in healthy male human subjects. A total of 14 college students was selected to participate in the study on a voluntary basis and each served as his own control. The study had two 17-day feeding periods. During the first feeding period, half of the subjects served as controls, the other as experimentals. During the second feeding period, treatments were crossed. When serving as controls, subjects consumed a low-fiber basal diet; when serving as experimentals, the same diet was supplemented with 25 g/day of soy polysaccharide. Blood samples taken at the beginning (days -1 and 1) and at the end (days 17 and 18) of each period revealed no changes in serum lipid levels or other blood parameters by soy polysaccharide supplementation. Nutrient balance and fecal transit studies revealed a significant increase in fecal wet weight and fecal water content, but no changes in total dry weight, fecal neutral steroid, bile salt, protein, and mineral contents. Glucose tolerance tests conducted during each period revealed that addition of soy polysaccharide to the glucose solution significantly reduced the reactive hypoglycemia at 180 min. Results of the present study suggest that in healthy male subjects, supplementation of soy polysaccharide can result in an increase in wet fecal content and possibly some improvement in glucose tolerance response.

Adult↗
PubMedDate not supplied

Polysaccharide antigens of Pseudomonas aeruginosa.

Cell-surface polysaccharide antigens of Pseudomonas aeruginosa are important determinants of pathogenicity and represent target antigens for the development of vaccines. Two major and distinct cell-surface polysaccharides are expressed by different strains of P. aeruginosa: the serotype determinant located on the O polysaccharide side chain of the lipopolysaccharide and mucoid exopolysaccharide (MEP), an antigen usually made by isolates of P. aeruginosa from patients with cystic fibrosis. The serotype determinant has been isolated in a high-molecular-weight, non-toxic, immunogenic form known as high-molecular-weight polysaccharide. High-molecular-weight polysaccharide is safe and immunogenic in humans and elicits T cell immunity to P. aeruginosa infection in animals. Purified MEP antigen has been shown to be immunogenic in animals, and patients with cystic fibrosis colonized with mucoid P. aeruginosa respond to MEP with the production of high-titered serum antibody. In spite of brisk immune responses of patients with cystic fibrosis to MEP, they are unable to deal with the chronic respiratory colonization by mucoid P. aeruginosa. An association has been established between the presence of opsonic-killing antibody to MEP and the lack of colonization of older patients with cystic fibrosis with P. aeruginosa.

Antibodies, Bacterial↗
PubMedDate not supplied

Immunochemical characterization of the polysaccharide antigens of group B streptococci.

Mouse monoclonal antibodies were used in the immunochemical characterization of the polysaccharide antigens of group B streptococci (GBS). Monoclonal antibodies specific for the sialylated form of the GBS type III polysaccharide were highly protective in a mouse model of GBS type III infection, whether of IgM, IgG2a, or IgA isotypes, but monoclonal antibodies specific for the nonsialylated form of the type III antigen were not protective, regardless of isotype. Monoclonal antibodies reacting with the type II polysaccharide antigen could be divided into two general antigen binding groups on the basis of the ability of beta-methylgalactopyranoside to inhibit their binding to purified type II antigen. Various proportions of antibodies with the two specificities were observed in rabbit and human sera. Although it was previously reported that rabbit antisera could not distinguish between the sialylated and nonsialylated forms of the type Ib polysaccharide, mouse monoclonal antibodies were found to exhibit exclusive specificity for one or the other form of the antigen. Only monoclonal antibodies specific for the sialylated Ib polysaccharide were protective in a mouse model.

Animals↗
PubMedDate not supplied

Polysaccharide antigens of Escherichia coli.

The major surface antigens of Escherichia coli are the cell wall lipopolysaccharides (LPS; O antigens) and the capsular polysaccharides (PS; K antigens). These polysaccharides are synthesized at the cytoplasmic membrane of the bacteria; the LPS are transported to the outer membrane, where they reside, whereas the PS are secreted into capsules. The LPS consist of lipid A covalently linked to the core oligosaccharide, which itself is covalently linked to the O-specific polysaccharide. The latter, which determines the O specificity of the bacteria may be neutral or contain negative charges (carboxyl groups or phosphate). The relatedness of E. coli to other genera (e.g., Klebsiella or Shigella) frequently is borne out by structural identity. This intergeneric relation is paralleled by similar pathogenic properties of the bacteria in question. The capsular antigens of E. coli are acidic polysaccharides, which can be divided into groups (I and II) on the basis of molecular size, nature of the acidic component, coexpression with O antigens, and temperature regulation of their biosynthesis. The major acidic components are hexuronic acid (mainly of Klebsiella-like group I) as well as 2-keto-3-deoxy-D-mannooctulonic acid, N-acetylneuraminic acid, or phosphate (mainly in Neisseria- and Haemophilus-like group II). Relatedness of encapsulated E. coli to encapsulated bacteria of other genera (Neisseria, Haemophilus, Klebsiella) is based on structural identity or similarity of the respective capsules. Identity not only refers to structure and serology of these capsules but also to the pathogenicity of the respective bacteria (e.g., E. coli K1 and Neisseria meningitidis b). Bacterial pathogenicity may be caused by the host's inability to raise an immune response to bacterial capsules (E. coli K1 and K5) because of the identity of the capsular polysaccharides and the host carbohydrates. This can be described as camouflage used by the bacteria as a strategem for bacterial virulence.

Antigens, Bacterial↗
PubMed2000

A sulfated polysaccharide from the sarcoplasmic reticulum of sea cucumber smooth muscle is an endogenous inhibitor of the Ca(2+)-ATPase.

Vesicles derived from the endoplasmic reticulum of sea cucumber smooth muscle retain a membrane bound Ca(2+)-ATPase that is able to transport Ca(2+) into the vesicles at the expense of ATP hydrolysis. In contrast with vesicles obtained from rabbit muscles, the activity of the Ca(2+)-dependent ATPase from sea cucumber is dependent on monovalent cations (K(+)>Na(+)>Li(+)). With the addition of highly sulfated polysaccharide to vesicle preparations from rabbit muscle, Ca(2+) uptake decreases sharply and becomes highly sensitive to monovalent cations, as observed with vesicles from sea cucumber muscle. These results led us to investigate the possible occurrence of a highly sulfated polysaccharide on vesicles from the endoplasmic reticulum of sea cucumber smooth muscle, acting as an "endogenous" Ca(2+)-ATPase inhibitor. In fact, vesicles derived from the invertebrate, but not from rabbit muscle, contain a highly sulfated polysaccharide. This compound inhibits Ca(2+) uptake in vesicles obtained from rabbit muscle and the inhibition is antagonized by monovalent cation. In addition, sea cucumber muscles contain high concentrations of another polysaccharide, which surrounds the muscle fibers, and was characterized as a fucosylated chondroitin sulfate. Possibly the occurrence of sulfated polysaccharides in the sea cucumber muscles is related with unique properties of the invertebrate body wall, which can rapidly and reversibly alter its mechanical properties, with change in length by more than 200%.

Animals↗
PubMed2006

Overproduction and increased molecular weight account for the symbiotic activity of the rkpZ-modified K polysaccharide from Sinorhizobium meliloti Rm1021.

K polysaccharides (KPSs) of Sinorhizobium meliloti strains are strain-specific surface polysaccharides analogous to the group II K antigens of Escherichia coli. The K(R)5 antigen of strain AK631 is a highly polymerized disaccharide of pseudaminic and glucuronic acids. During invasion of host plants, this K antigen is able to replace the structurally different exopolysaccharide succinoglycan (EPS I) and promotes the formation of a nitrogen-fixing (Fix(+)) symbiosis. The KPS of strain Rm1021 is a homopolymer of 3-deoxy-D-manno-2 octulosonic acid (Kdo). The Kdo polysaccharide is covalently linked to the lipid anchor, has a low molecular weight (LMW), and is symbiotically inactive. On introduction of the Rm41-specific rkpZ gene into strain Rm1021, a modified KPS is expressed that is able to substitute EPS I during symbiosis with the host plant. To better understand the nature of modification conferred by rkpZ, we performed a structural analysis of the KPS using nuclear magnetic resonance (NMR), electrospray ionization-mass spectrometry (ESI-MS), and gas chromatography (GC-MS). The modified KPS retained primary polyKdo structure, but its degree of polymerization (DP) and level of production were increased significantly. In contrast to the wild-type polyKdo, only a part of polyKdo was lipidated. Shorter polysaccharide chains were lipid-free, whereas longer polysaccharide chains were lipidated. Sinorhizobium meliloti Rm1021 was found to carry two paralogs of rkpZ. Both genes are involved in polyKdo production, but they only show partial functional activity as compared with the rkpZ of Rm41.

Bacterial Proteins↗
PubMed1976

The polysaccharide capsule of Bacteroides fragilis subspecies fragilis: immunochemical and morphologic definition.

A large-molecular-weight capsular polysaccharide was isolated from strains of Bacteroides fragilis subspecies fragilis. By means of electron microscopy and staining with ruthenium red, the thick polysaccharide capsule was also visualized. With use of a radioactive antigen-binding assay, antibody to this capsular polysaccharide was demonstrated in antisera prepared in rabbits to each of eight strains of B. fragilis fragilis. Antibody of similar specificity was not found in antisera prepared to Bacteroides melaninogenicus or to strains of Bacteroides fragilis subspecies vulgatus and Bacteroides fragilis subspecies distasonis; such antibody was found in antisera to only one of two strains of Bacteroides fragilis subspecies thetaiotaomicron. The radioactive antigen-binding assay is a sensitive test for the detection of antibody to capsular polysaccharide. This polysaccharide antigen may form the basis of a serogrouping system for B. fragilis.

Antigen-Antibody Complex↗
PubMed1979

Comparative immunogenicity of vaccines prepared from capsular polysaccharides of group C Neisseria meningitidis O-acetyl-positive and O-acetyl-negative variants and Escherichia coli K92 in adult volunteers.

Three structurally and antigenically similar capsular polysaccharides, two derived from group C Neisseria meningitidis (O-acetyl-positive and O-acetyl-negative variants) and one from Escherichia coli K92, which cross-reacts with polysaccharide from group C N. meningitidis, were compared for their ability to induce anticapsular and bactericidal antibodies to group C N. meningitidis in adult volunteers. All three vaccines elicited group C-specific serum antibodies. The vaccine derived from the O-acetyl-negative variant was the most immunogenic of the three vaccines. With use of radiolabeled O-acetyl-positive group C N. meningitidis polysaccharide antigen, the geometric mean titers of antibody in serum were 41.7 microgram/ml to the O-acetyl-negative variant, 22.8 microgram/ml to the O-acetyl-positive variant, and 7.1 microgram/ml to E. coli K92. Antibodies induced by all three vaccines were bactericidal for both of the group C N. meningitidis polysaccharide variants. An inverse relation between the comparative immunogenicity of the O-acetyl-negative polysaccharide and the virulence of group C N. meningitidis was found.

Adult↗
PubMed1992

Thymus-independent and thymus-dependent responses to polysaccharide antigens.

Immune responses to polysaccharide antigens are thymus-independent (TI). Conversion of a polysaccharide antigen to a thymus-dependent (TD) antigen by covalent coupling to an immunogenic protein carrier alters the response to the polysaccharide in several important ways. Of primary importance for the prevention of invasive diseases in infants caused by encapsulated bacteria is the shift of the peak antibody response to a much younger age. Another important change is the development of memory B cells primed and ready to respond to either the polysaccharide, as would be encountered during an infection, or to a second dose of the same antigen. Additional immunoglobulin isotypes not seen or seen as a minor component in response to the polysaccharide are also a feature of the TD response. Finally, the diversity of the antibody population is increased after immunization with a TD vaccine compared with that seen after immunization with a TI vaccine.

Animals↗
PubMed1995

A trial of a group A plus group C meningococcal polysaccharide-protein conjugate vaccine in African infants.

The safety and immunogenicity of a group A plus group C meningococcal polysaccharide-CRM197 conjugate vaccine was evaluated in 304 8- to 10-week-old Gambian infants. Infants were immunized with one, two, or three doses of conjugate vaccine or with two doses of a meningococcal A plus C polysaccharide vaccine. The conjugate vaccine produced few systemic side effects, and local reactions were similar to those produced by the polysaccharide vaccine. Postvaccination group A meningococcal polysaccharide antibody levels, measured by ELISA, increased progressively after one, two, or three doses of conjugate vaccine. However, one dose of conjugate vaccine given at the age of 6 months induced a higher group C meningococcal antibody response than did two doses of conjugate vaccine given at 2 and 6 months. Two doses of conjugate vaccine induced higher levels of antibody than did two doses of polysaccharide vaccine. Thus, this new meningococcal conjugate vaccine proved to be safe and immunogenic.

Antibodies, Bacterial↗
PubMed1995

Immunogenicity and protective activity in animals of a type V group B streptococcal polysaccharide-tetanus toxoid conjugate vaccine.

The recent recognition of type V strains as a frequent cause of group B streptococcal (GBS) infection in both infants and adults prompted investigation of an effective vaccine against these organisms. Purified GBS type V polysaccharide was covalently linked to tetanus toxoid to form a type V polysaccharide-tetanus toxoid conjugate vaccine. The conjugate elicited type V polysaccharide-specific IgG antibodies in rabbits, while unconjugated type V polysaccharide did not. Conjugate-induced rabbit antibodies were opsonic in vitro and protected mice against challenge with type V GBS. Efficacy of the conjugate vaccine also was demonstrated in a maternal vaccination/neonatal challenge model in mice. A GBS type V polysaccharide-tetanus toxoid conjugate is an effective immunogen in animal models and may be a useful component for inclusion in a multivalent GBS vaccine for human use.

Animals↗
PubMed1995

Complement-mediated bactericidal activity of human antibodies to poly alpha 2-->8 N-acetylneuraminic acid, the capsular polysaccharide of Neisseria meningitidis serogroup B.

Serum antibodies to Neisseria meningitidis group B (MenB) polysaccharide are reported not to elicit bacteriolysis in the presence of human complement. To reexamine this question, we evaluated the ability of two human IgM anti-MenB polysaccharide monoclonal antibodies (MAbs) and seven human MenB polysaccharide-reactive human IgM paraproteins to elicit bacteriolysis. In the presence of human complement, both MAbs and five of the seven paraproteins were bactericidal at antibody concentrations of 0.25-9.6 micrograms/mL (50% killing). Activity of the respective antibodies was enhanced 200- to > 10,000-fold when rabbit complement was used instead of human complement. With rabbit complement, the bactericidal activity of human IgM polyclonal antibody or MAb to Haemophilus influenzae type b (Hib) polysaccharide but not human IgG polyclonal antibody or MAb to Hib polysaccharide was similarly augmented. Thus, for both MenB and Hib, IgM antipolysaccharide antibodies elicit complement-mediated bactericidal activity in the presence of human complement, and the use of rabbit complement yields spuriously high activity.

Animals↗
PubMed1996

Quantitative determination of antibodies to type III group B streptococcal polysaccharide.

The susceptibility of neonates to invasive infection with type III group B streptococci (GBS) in a radioactive antigen-binding assay (RABA) has been correlated with low maternal serum levels of capsular polysaccharide-specific antibodies. An ELISA was developed using capsular polysaccharide covalently coupled to human serum albumin. In sera from 35 healthy women, the range of IgG antibodies to GBS III polysaccharide was 0.05-33.0 micrograms/mL, and specific IgA antibodies were 0.08-1.1 micrograms/mL; however, no GBS III capsular polysaccharide-specific antibodies of the IgM isotype were detected by the ELISA. The levels of naturally acquired and vaccine-induced antibodies obtained with this ELISA correlated well with the results of the RABA (Spearman's rank correlation coefficient, .92). The ELISA has two major advantages over the RABA: It measures specific isotypes and subclasses of antibodies, and it can detect type III polysaccharide-specific antibodies at lower concentrations.

Animals↗