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PubMed1976

The specificity of naturally occurring heterophile antibodies in normal rabbit serum.

Rabbit sera used as a complement source contain cytotoxic antibodies which reacted with cultured human cells. This cytotoxic activity can be inhibited by human IgM. The capacity of IgM mu and L chains, and IgM glycopeptides to inhibit these heterospecific antibodies was determined. The inhibitory activity of several monosaccharides, bacterial polysaccharides and blood group substances was also determined. At least some of the heterospecific antibodies in normal rabbit sera are directed against carbohydrate determinants. Mannose, fucose, and bacterial polysaccharides containing mannose as the immunodominant sugar are particularly effective in inhibiting cytotoxic antibodies.

ABO Blood-Group System↗
PubMed1996

Structure and conformation of acetan polysaccharide.

Acetan is an anionic bacterial polysaccharide. The chemical repeat unit consists of a cellobiose unit solubilised by attachment of a charged pentasaccharide sidechain to one of the glucose residues. The repeat unit contains two sites of acetylation. 1H and 13C NMR studies, coupled with both basic-methylation and mild-methylation studies, have shown that acetylation occurs at C6 on the (1,2)D-Man and the (1,34)D-Glc residues. A variety of techniques including NMR, optical rotation, circular dichroism and DSC show evidence for a thermoreversible conformational order (helix)-disorder (coil) transition for acetan in aqueous solution. The studies suggest that acetylation of the backbone does not prevent helix formation.

Acetylation↗
PubMedDate not supplied

Effect of addition of water-soluble polysaccharides on bacterial cellulose production in a 50-L airlift reactor.

Bacterial cellulose (BC) production was carried out in a batch cultivation of Acetobacter xylinum in a 50-L internal loop airlift reactor by addition of water-soluble polysaccharides into the medium. When 0.1% (w/w) agar was added, BC production reached 8.7 g/L compared with 6.3 g/L in the control, and duration of the cultivation period to reach the maximum concentration of BC was almost half of that without addition of polysaccharides. During cultivation, BC was formed into pellets whose size was smaller when the productivity of BC was higher, indicating that increase in the relative viscosity by addition of polysaccharides hindered formation of large clumps of BC and increase in the volumetric oxygen transfer coefficient at high flow rate led to increase in BC productivity.

Acetobacter↗
PubMed1990

Chromotropic character of bacterial acidic polysaccharides: Part III--Interaction of cationic dye pinacyanol chloride with Klebsiella K15 capsular polysaccharide.

Interaction of cationic dye pinacyanol chloride with the acidic capsular polysaccharide isolated from Klebsiella serotype K15 has been investigated by spectral measurements. Klebsiella K15 polysaccharide consists of hexasaccharide repeating units containing one residue each of glucuronic acid and glucose, and four residues of galactose. Glucuronic acid acts as the potential anionic site and the biopolymer interacts with the dye cations. It induces metachromasy in the dye and a blue shift of about 100 nm is observed in the visible absorption spectrum of the dye. Spectral measurements have been carried out at different polymer/dye molar ratios. Stoichiometry of polymer and dye in the polyanion-dye compound (1:1) indicates that every potential anionic site of the polyanion is associated with the dye cation, and stacking conformation is thus suggested. Effect of different non-aqueous solvents in reversing metachromasy has also been studied. Interaction studies exhibit chromotropic character of the biopolymer.

Bacterial Capsules↗
PubMed1999

Size fractionation of bacterial capsular polysaccharides for their use in conjugate vaccines.

We have developed a chromatographic method suitable for the fractionation of polysaccharides having a negatively charged group. The method permits the removal of all those polysaccharide fragments having a short sequence and which are likely unsuitable for conjugate vaccine construction. The selected polysaccharide fragments can be used to produce glycoconjugate vaccines containing a restricted saccharide polydispersion. We have applied this chromatographic method to three different antigens, Haemophilus influenzae type b and Neisseria meningitidis group A and group C polysaccharides. The method is easily adapted for manufacturing purposes.

Antigens, Bacterial↗
PubMed1991

Effects of hemorrhage and resuscitation on bacterial antigen-specific pulmonary plasma cell function.

BACKGROUND AND METHODS: Nosocomial pneumonia is frequent after hemorrhage and trauma, and often contributes to multiple organ system failure, morbidity, and mortality in this setting. Although the percentages and numbers of resting pulmonary B cells (clonal precursors) able to be stimulated to produce antibodies to bacterial antigens are markedly decreased after hemorrhage, the effects of hemorrhage on the pulmonary plasma cells actually producing antibody to bacterial antigens have not been examined. To investigate this question, mice were bled 30% blood volume, then resuscitated with the shed blood 1 hr later. At predetermined times after hemorrhage, the mice were intranasally immunized with liposomes containing the bacterial polysaccharide antigen levan (from Aerobacter levanicum). One week later, lung lavages were performed to measure bacterial antigen-specific secretory immunoglobulin A (sIgA) titers and the numbers of intraparenchymal pulmonary plasma cells producing antibody against the bacterial antigen were determined. RESULTS: Reduced numbers of pulmonary plasma cells producing antibody against the immunizing bacterial polysaccharide antigen were found between 1 and 14 days after blood loss, and titers of bacterial antigen-specific secretory IgA were decreased for greater than 2 wks after hemorrhage. The importance of these abnormalities in pulmonary B-cell function was demonstrated by an increased susceptibility to Pseudomonas aeruginosa pneumonia in mice infected 4 days after hemorrhage, when bacterial antigen-specific pulmonary plasma cell numbers were at their lowest point. Resuscitated mice showed the same increased susceptibility to P. aeruginosa pneumonia as did hemorrhaged but unresuscitated animals. CONCLUSIONS: Hemorrhage, even if resuscitated, results in alterations in bacterial antigen-specific pulmonary B-cell function and secretory IgA production that are profound, long lasting, and associated with increased susceptibility to infection at this mucosal surface. Because these effects on pulmonary B-cell function do not occur immediately after hemorrhage, immunization techniques able to enhance bacterial antigen-specific secretory IgA titers at pulmonary surfaces may be able to increase resistance to nosocomial pneumonia if administered shortly after injury and blood loss.

Animals↗
PubMedDate not supplied

The effect of NaF on the bacterial production of polysaccharide and subsequent adsorption on hydroxyapatite.

The affinity of some bacterial polysaccharides for hydroxyapatite was investigated. Water insoluble polysaccharide production by bacteria was inhibited by the presence of NaF in the growth medium, while the water soluble fraction was unaffected. The adsorption of the bacterial polysaccharide on hydroxyapatite decreased with decreasing levels of the water insoluble fraction. It is suggested that NaF can inhibit bacterial attachment and caries by interfering with bacterial attachment through reducing the production of water insoluble polysaccharide.

Adsorption↗
PubMedDate not supplied

Differences in IgM synthesis to gut bacterial peptidoglycan polysaccharide after burn injury and gut ischemia.

Both burn injury and intestinal ischemia have been proven to induce bacterial translocation from the gut. It is still unknown, however, whether the bacteria induces immune response in these different models. To assess this, we measured in vitro IgM synthesis to peptidoglycan polysaccharide (PGPS), a ubiquitous gut bacterial antigen, after burn injury or gut ischemia-reperfusion in a mouse model. Eighty-five BALB/c mice were divided into four groups. Gut ischemia was produced by placing a vessel loop around the superior mesenteric artery at celiotomy (group Isc; n = 31). After 45 minutes, the abdomen was reopened, and the vessel loop removed. All animals had visible gut ischemia. Control mice (group Isc-C; n = 15) underwent two sham operations. Burn injury was 25% body surface area full-thickness to the dorsum (group B; n = 27). Another control group (B-C; n = 12) was also used. Animals were euthanized 24 hours after recirculation or 5 days after the burn injury. All spleens were removed, and cell suspensions prepared. Cells were cultured in 2.5 micrograms/ml lipopolysaccharide for 5 days, and anti-PGPS IgM level in the supernatant was measured by an enzyme-linked immunosorbent assay. Intestinal ischemia produced a significant rise in in vitro anti-PGPS IgM synthesis per 10(5) lymphocytes, which is the principal immunoglobulin response to infection. However, anti-PGPS IgM in mice after burn injury was significantly decreased. This decreased IgM synthesis after burn injury compared to gut ischemia may represent continued immune impairment from the burn wound, and may account for organ dysfunction related to bacterial translocation after burn injury.

Animals↗
PubMed1985

Recurrent sinopulmonary infection and impaired antibody response to bacterial capsular polysaccharide antigen in children with selective IgG-subclass deficiency.

We studied 20 children with recurrent sinopulmonary infections and serum IgG levels within the normal range, who had selective IgG-subclass deficiency. Twelve of the children were IgG2 deficient, five were IgG3 deficient, and three were deficient in both IgG2 and IgG3. IgA deficiency was present in 3 of the 20 patients. In the children with IgG2 deficiency, serum antibody concentrations to the capsular polysaccharide of Hemophilus influenzae type B (Hib) were significantly lower than those in age-matched controls, both before and after immunization with the Hib capsular polysaccharide antigen, which elicits antibody predominantly of the IgG2 subclass. In contrast, their serum antibody titers to the tetanus and diphtheria toxoid protein antigens, which elicit antibody predominantly of the IgG1 subclass, were normal in comparison with those of age-matched controls. These results suggest that impairment of the antibody response to specific microbial antigens predisposes patients with selective IgG-subclass deficiencies to recurrent infections. Thus, as an aid in determining therapy, children with recurrent infections and normal total serum IgG should be evaluated for this condition.

Adolescent↗
PubMed2005

In-source fragmentation and analysis of polysaccharides by capillary electrophoresis/mass spectrometry.

In order to develop a robust and easy-to-use technique for characterization of bacterial polysaccharides, a pseudo-hydrolysis strategy was investigated. Based on in-source collision-induced dissociation, polysaccharide molecular ions were fragmented within the orifice-skimmer region of an electrospray ionization (ESI) mass spectrometer. The fragment ions thus generated were then analyzed similarly to the conventional ESI mass spectrometry approach. MS/MS scanning was applied to obtain product-ion spectra of the primary fragments for sequencing. To further improve the sensitivity and separation of polysaccharides from other components in the samples, a pressure-assisted capillary electrophoresis/mass spectrometry (CE/MS) system was employed. Using bacterial polysaccharides as model compounds, the mass spectra obtained for polysaccharide repeating units generated through chemical hydrolysis and in-source fragmentation were directly compared, both in positive and negative ion modes. With the additional separation of impurities provided by CE, the success of this technique has been demonstrated for structural analysis of O-chain polysaccharides (O-PS) and capsular polysaccharides (CPS). In-source fragmentation was applied to promote the formation of structurally relevant repeating units of heterogeneous CPS that would remain undetected using conventional ESI conditions. This approach was proven to be particularly useful for probing the subtle structural differences in monosaccharide composition and functionalities arising across bacterial serotypes.

Aeromonas↗
PubMed1987

Rapid diagnosis of pneumonia in children.

Antigen detection techniques are available for the identification of bacterial polysaccharides, viruses, and chlamydia. Viruses and chlamydia are detected by direct immunofluorescence (DFA) or enzyme immunoassay (EIA). Bacterial polysaccharides are detected by latex agglutination or staphylococcal coagglutination of serum or concentrated urine. Most studies have not compared these techniques to the gold standard of lung puncture, so the role of dual infections with bacteria and viruses cannot be adequately determined. The sensitivity of any of these techniques is dependent on the quality of the antisera used. Monoclonal sera are now available for the detection of most viruses and seem to be as sensitive as polyclonal sera. DFA or EIA may offer equal sensitivity but their advantages and disadvantages must be considered by the local diagnostic laboratories. Most DFA and EIA systems have a sensitivity of 90% when compared with viral cultural for the identification of the organism. Agglutination reagents are available commercially for the detection of pneumococcal and Hemophilus influenzae type b polysaccharides. The sensitivity and specificity of each brand should be determined on serum or urine from patients known to have positive blood cultures and those free of disease. The brand chosen should be the one that has reasonable sensitivity and specificity. Rapid diagnostic techniques are helpful if they are used within a clinical context and they are positive. Negative tests do not rule out infection.

Antigens, Bacterial↗
PubMed2006

Introduction of air in the anaerobic culture of Streptococcus pneumoniae serotype 23F induces the release of capsular polysaccharide from bacterial surface into the cultivation medium.

AIM: An approach to increase Streptococcus pneumoniae capsular polysaccharide (CPS) in the culture medium during fed-batch cultivation in bioreactor. METHODS AND RESULTS: Streptococcus pneumoniae serotype 23F was cultivated in a 5-l bioreactor with nitrogen-sparging and followed by addition of air in the stationary phase. The amount of CPS released in the supernatant progressively increased under air sparging. The profile of cellular viability and optical density was similar in both cultures. Immunoelectron microscopy showed that the amount of tightly cell-bound CPS was higher in bacteria cultivated under nitrogen than under air. CONCLUSIONS: The stress caused by the addition of air at the stationary phase promoted a large increase of free CPS into the medium, as a consequence of the morphologic change in the capsule. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of air in the stationary phase of the culture would greatly simplify the subsequent downstream process, allowing CPS purification from the supernatant. The direct consequence of this process improvement is the reduction of vaccine production costs.

Air↗
PubMed2004

Bacterial capsular polysaccharide and sugar transferases.

Capsular polysaccharides (CPs) of several pathogenic bacteria are thought to be good materials for the development of new therapeutic reagents. These polysaccharides can be used as vaccines against infection of pathogenic bacteria and are also useful as inhibitors for disease caused by aberrant and abnormal cell-cell interaction, such as cancer metastasis and inflammation. Since bacterial CPs are diverse in structure and these bacteria have a variety of sugar transferases responsible for the synthesis of CPs, bacterial CP synthesis (cps) genes have attracted much interest as a source of glycosyltransferases useful for glycoengineering. In this review, we describe physiological effects of the bacterial CPs on mammalian cells, and the structure and function of the cps genes, by focusing on group B streptococci, Streptococcus agalactiae type Ia and Ib, that produce high-molecular weight polysaccharides consisting of the following pentasaccharide repeating units: -->4)-[alpha-D-NeupNAc-(2-->3)-beta-D-Galp-(1-->4)-beta-D-GlcpNAc-(1-->3)]-beta-D-Galp-(1-->4)-beta-D-Glcp-(1--> and -->4)-[alpha-D-NeupNAc-(2-->3)-beta-D-Galp-(1-->3)-beta-D-GlcpNAc-(1-->3)]-beta-D-Galp-(1-->4)beta-D-Glcp-(1-->, respectively.

Amino Acid Sequence↗
PubMed1996

Blocking adhesion of cancer cells to endothelial cell types by S. agalactiae type-specific polysaccharides.

By using immortalized and normal endothelial cells, we were able to detect inhibitory effects of type specific polysaccharides from Streptococcus agalactiae on adhesion of cancer cells to endothelial cells, which is an essential step of cancer metastatis. The inhibition was probably due to specific structures of the bacterial polysaccharides, since the structures of the saccharides are very similar to those of cancer specific sialyl Lewis carbohydrates (sialyl Le(a) and Le(x)) which bind to ELAM-1 of endothelial cells. This result indicated that the bacterial polysaccharides from S. agalactiae could be very useful and hopeful as cancer metastasis inhibitors.

Antineoplastic Agents↗
PubMed2006

Characterization of the opsonic and protective activity against Staphylococcus aureus of fully human monoclonal antibodies specific for the bacterial surface polysaccharide poly-N-acetylglucosamine.

Carbohydrate antigens are important targets of the immune system in clearing bacterial pathogens. Although the immune system almost exclusively uses antibodies in response to foreign carbohydrates, there is still much to learn about the role of different epitopes on the carbohydrate as targets of protective immunity. We examined the role of acetyl group-dependent and -independent epitopes on the staphylococcal surface of polysaccharide poly-N-acetylated glucosamine (PNAG) by use of human monoclonal antibodies (MAbs) specific for such epitopes. We utilized hybridoma technology to produce fully human immunoglobulin G2 (IgG2) MAbs from B cells of an individual post-Staphylococcus aureus infection and cloned the antibody variable regions to produce an IgG1 form of each original MAb. Specificity and functionality of the purified MAbs were tested in vitro using enzyme-linked immunosorbent assays, complement deposition, and opsonophagocytic assays. We found that a MAb (MAb F598) that bound the best to nonacetylated or backbone epitopes on PNAG had superior complement deposition and opsonophagocytic activity compared to two MAbs that bound optimally to PNAG that was expressed with a native level (>90%) of N-acetyl groups (MAbs F628 and F630). Protection of mice against lethality due to S. aureus strains Mn8 and Reynolds further showed that the backbone-specific MAb had optimal protective efficacy compared with the acetate-specific MAbs. These results provide evidence for the importance of epitope specificity in inducing the optimal protective antibody response to PNAG and indicate that MAbs to the deacetylated form of PNAG could be immunotherapeutic agents for preventing or treating staphylococcal infections.

Acetylglucosamine↗
PubMed1999

A brief history of pneumococcal vaccines.

Attempts to control pneumococcal infection by vaccination, undertaken initially in 1911, have gone through 3 phases during the subsequent 8 decades. Initially, vaccines of killed pneumococcal cells prepared in a variety of ways were used in epidemic settings with inconclusive results, although administered to approximately 1 million recipients. The discovery that adults injected with small amounts of purified capsular polysaccharide developed antibodies to the homologous capsular type led to the trial of a tetravalent vaccine that showed conclusively its ability to prevent infection by the types represented in it. With the advent of penicillin and other effective antipneumococcal drugs, interest in prophylaxis waned. Interest in vaccination was revived only after demonstration that some segments of the population remained at high risk of death if infected and after the emergence of multidrug-resistant pneumococci. Infants and young children, among whom the incidence of pneumococcal infection is high, respond poorly to purified bacterial polysaccharides but develop satisfactory responses to bacterial polysaccharides when these are linked chemically to a protein. The early results of trials with such polysaccharide protein conjugate vaccines give promise that control of a significant portion of pneumococcal infection in the paediatric population will soon be feasible.

Bacterial Vaccines↗
PubMed1986

Correlation of the Km(1) immunoglobulin allotype with anti-polysaccharide antibodies in Caucasian adults.

Km allotype antigens are serologic markers expressed on kappa light chains of human immunoglobulins. To determine whether th Km phenotype of an individual is related to his ability to make antibodies to polysaccharide antigens, we correlated the Km allotypes of 129 healthy caucasian adults with the concentrations of specific antibodies to three bacterial polysaccharide antigens after immunization. The 14 individuals expressing the Km(1) allotype had lower concentrations of IgG, IgM, and IgA antibodies by enzyme-linked immunosorbent assay and total antibody by radioimmunoassay to Haemophilus influenzae type b and Neisseria meningitidis group C capsular polysaccharides when compared with the 115 Km(1) negative individuals. The Km-associated differences in H. influenzae type b and N. meningitidis group C antibody concentrations were confined to kappa light chain-containing antibody (P = 0.029 and 0.003, respectively). Similarly, the Km(1) positives had slightly lower kappa chain-containing Ig than the Km(1) negatives (P = 0.079). We conclude that genes in or near the kappa light chain locus play a role in the regulation of kappa-containing antibody production to some bacterial polysaccharides and perhaps to other antigens.

Adult↗