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PubMed1963

NEW BACTERIAL POLYSACCHARIDE FROM ARTHROBACTER.

A bacterial strain (NRRL B-1973) isolated from soil at Guatemala City and tentatively identified as an Arthrobacter species produced a polysaccharide with unusual properties. Conditions were studied for the production of this microbial gum in shaken flasks and 20-liter fermentors. Suitable nutrients for optimal polysaccharide production included 3% glucose, 0.3% enzyme-hydrolyzed casein, magnesium sulfate, manganese sulfate, and potassium phosphate buffer (pH 7.0). Polysaccharide yields ranged from 40 to 45%, based on initial dextrose in the medium in 3- or 4-day fermentations. The gum was readily recovered from culture fluid by alcohol precipitation in the presence of an electrolyte. The Arthrobacter gum exhibited characteristics unique for a polyelectrolyte. Viscosity of solutions was not decreased by heating in the presence of salt, and the gum withstood a temperature of 121 C for 30 min. At polysaccharide levels above 0.75%, gels were formed when solutions were autoclaved with KCl. There was no significant change in viscosity over a pH range of 5.0 to 10.0.

Arthrobacter↗
PubMed1992

Intranasal immunization with bacterial polysaccharide containing liposomes enhances antigen-specific pulmonary secretory antibody response.

Enhancement of bacterial antigen-specific secretory IgA (sIgA) titres in the lungs may enhance resistance to infections, such as pneumonia, occurring at this mucosal surface. To examine this issue, we intranasally administered liposomes containing bacterial polysaccharide antigens from Aerobacter levanicum, Pseudomonas aeruginosa and Streptococcus pneumoniae. In each case, increased titres of bacterial polysaccharide-specific sIgA could be achieved in the lungs following intranasal immunization with antigen encapsulated in liposomes. In comparison with oral immunization, which required high doses of polysaccharide antigen even when coadministered with adjuvant, intranasal administration of liposomes containing polysaccharide antigens achieved a similar pulmonary sIgA response with approximately 1/30 the amount of antigen necessary with oral immunization. In the case of P. aeruginosa, the magnitude of the sIgA response following intranasal immunization was sufficient to significantly reduce mortality from pneumonia produced by this organism. These results demonstrate that liposome-based mucosal immunization strategies can induce increased bacterial polysaccharide antigen-specific sIgA titres in the lung, and reduce susceptibility to pneumonia.

Administration, Intranasal↗
PubMed1993

The in vivo antibody response in rat gut-associated lymphoid tissue (GALT) after immunization with bacterial polysaccharide antigen.

Gut mucosal immune responses to bacterial polysaccharide antigen in rats were investigated in vivo. Rats were immunized with pneumococcal polysaccharide type 3 (PPS-3) via different routes, i.e. in the Peyer's patch (iPP), in the colon (ic), in the peritoneal cavity (ip), and intravenously (iv). The development of specific antibody-forming cells (AFC) and their isotypes in the intestinal mucosa, gut-associated lymphoid tissue (GALT), mesenteric lymph nodes (MLN) and spleen were studied by immunohistochemistry. Furthermore, the serum antibody levels were measured by enzyme-linked immunosorbent assay (ELISA). The results showed that iPP immunization evoked high numbers of anti-PPS-3 AFC of the IgA isotype in the mucosa of the small intestine and in the PP. On the contrary, the ic route did not elicit a mucosal response, though a few AFC were found in the MLN and spleen. Following ip priming, a specific IgA response was found, especially in MLN and spleen, and a low response was detected in the villi. A high response was found in the parathymic lymph nodes (PTLN). Iv immunization gave rise to the development of AFC in the spleen, particularly of the IgM isotype. We failed to induce mucosal responses to PPS-3 antigen in the colon, irrespective of the route of immunization.

Animals↗
PubMed2000

Development and validation of an NMR-based identity assay for bacterial polysaccharides.

A method utilizing NMR spectroscopy has been developed to confirm the identity of bacterial polysaccharides used to formulate a polyvalent pneumococcal polysaccharide vaccine. The method is based on 600 MHz proton NMR spectra of individual serotype-specific polysaccharides. A portion of the anomeric region of each spectrum (5.89 to 4.64 ppm) is compared to spectra generated for designated reference samples for each polysaccharide of interest. The selected region offers a spectral window that is unique to a given polysaccharide and is sensitive to any structural alteration of the repeating units. The similarity of any two spectral profiles is evaluated using a correlation coefficient (rho), where rho >/= 0.95 between a sample and reference profile indicates a positive identification of the sample polysaccharide. This method has been shown to be extremely selective in its ability to discriminate between serotype-specific polysaccharides, some of which differ by no more than a single glycosidic linkage. Furthermore, the method is rapid and does not require extensive sample manipulations or pretreatments. The method was validated as a qualitative identity assay and will be incorporated into routine quality control testing of polysaccharide powders to be used in preparation of the polyvalent pneumococcal vaccine PNEUMOVAX 23. The specificity and reproducibility of the NMR-based identity assay is superior to the currently used colorimetric assays and can be readily adapted for use with other bacterial polysaccharide preparations as well.

Bacterial Vaccines↗
PubMed1994

Estimation of the sulfate content of hydrothermal vent bacterial polysaccharides by Fourier transform infrared spectroscopy.

Deep-sea hydrothermal vents are characterized by unusual chemical and physical parameters, including high pressure and temperature. In this extreme environment, unusual microorganisms of biotechnological importance survive. Polymer-producing bacteria have been specifically studied for several years with the aim of demonstrating their ability to produce unusual polysaccharides in terms of physical, chemical, and biological properties. Because sulfates play an important role in the biological properties of polysaccharides, it is very important to determine their content with accuracy. Fourier transform infrared spectroscopy (FT-IR) was used for sulfate analysis and the results were compared with those of other analytical techniques. We found a good correlation between FT-IR and other analytical techniques for sulfate concentrations ranging from 2.4 to 20%. The data indicated that this technique could be used to determine the chemical composition of the polymers along with a semiquantitative estimation of the sulfate content.

Electron Probe Microanalysis↗
PubMed1992

Bacterial polysaccharides, endotoxins, and immunomodulation.

These studies show that at least some--though certainly not all--of the adjuvant effects of LPS and its derivatives can be attributed to its ability to eliminate the inhibitory effects of Ts which are activated during the course of a normal immune response. The ability of nontoxic MPL to act in this fashion suggests that it can be used as a safe and acceptable alternative to Freund's complete adjuvant to increase the immunogenicity of poorly immunogenic antigens. More important, the ability of MPL to eliminate the expression of Ts activity, without adversely influencing other T cell functions (e.g., Th, Ta, and Tc activity) makes its use as an adjuvant even more promising since it can then permit those T cell functions to be expressed in a much more efficient manner. Obviously, this would have great significance for the development of tumor immunity.

Adjuvants, Immunologic↗