Lipopolysaccharides of Helicobacter pylori serogroups O:3 and O:6--structures of a class of lipopolysaccharides with reference to the location of oligomeric units of D-glycero-alpha-D-manno-heptose residues.

Lipopolysaccharides (LPS) from antigenically different strains assigned to serogroups O:3 and O:6 of Helicobacter pylori were isolated as water-soluble material of high Mr and as water-insoluble gels of low Mr. Chemical and spectroscopic analyses of the soluble LPS and oligosaccharides liberated from the water-insoluble gels led to proposed structures with Lewis (Le) antigen determinants terminating regular repeating units of different types, linked in turn to inner core regions of invariable structure. The O:6 LPS has two populations of related molecules with chains of 3-linked D-glycero-alpha-D-manno-heptose residues similar to those in the MO19 strain, one with and the other without a single terminal Lewis (Le(y)) epitope. In contrast, in the O:3 LPS, Lewis (Le(x) and Le(y)) epitopes terminate a partially fucosylated N-acetyllactosaminoglycan, but a heptan chain similar to that in the O:6 LPS was shown to connect the outer chains to the inner core. These LPS provide examples of the molecular mimicry of cell-surface glycoconjugates. Structural variations of LPS between strains, and differences in some aspects of structure within strains, between high Mr and low Mr LPS indicate a class of LPS whose mechanisms of biosynthesis lead to overall architectures different from those characteristic of most LPS from enteric bacteria.

Miller-Fisher syndrome associated with Campylobacter jejuni bearing lipopolysaccharide molecules that mimic human ganglioside GD3.

A Campylobacter jejuni strain of serotype O:10 was isolated from a patient who had Miller-Fisher syndrome. In its biochemical reactions and cellular morphology, the isolate was characteristic of typical C. jejuni. Antibodies against extracted lipopolysaccharide (LPS) were detected by passive hemagglutination in the acute- and convalescent-phase patient sera. By sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting with the O:10 antiserum, it was demonstrated that the strain possessed both low- and high-molecular-weight molecules. Chemical analysis of the LPS revealed that the core oligosaccharide has a terminal trisaccharide epitope consisting of two molecules of sialic acid linked to galactose, a structure reflecting the terminal region of human ganglioside GD3. As this trisaccharide is also present in LPS cores of serotype O:19 strains from patients with Guillain-Barré syndrome but not in cores of nonneuropathic C. jejuni, a possible role for the trisaccharide in the etiology of neuropathies is indicated, and a difference for distinguishing neuropathic strains from nonneuropathic strains may be the presence of a sialyltransferase required for the synthesis of this trisaccharide.

Lipo-oligosaccharide of Campylobacter lari strain PC 637. Structure of the liberated oligosaccharide and an associated extracellular polysaccharide.

Lipo-oligosaccharide from phenol-water extraction of cells of Campylobacter lari strain PC 637 was separated as a water-insoluble gel of low relative molecular mass (M(r)) from a water-soluble extracellular polysaccharide of high M(r). Structural investigations were performed on the lipo-oligosaccharide and the extracellular polysaccharide, variously using 1H, 13C, and 31P NMR spectroscopy, linkage analysis, and fast atom bombardment-mass spectrometry of permethylated derivatives of the glycans and their products of chemical and enzymic degradation. The following structures are proposed for the highly branched oligosaccharide region: [formula: see text] and for the tetraglycosyl phosphate repeating unit of the extracellular polysaccharide: [formula; see text]

Lipopolysaccharides from Campylobacter jejuni associated with Guillain-Barré syndrome patients mimic human gangliosides in structure.

Lipopolysaccharides extracted from Campylobacter jejuni serostrains (serotype reference strains) for serotypes O:4 and O:19 were found to have core oligosaccharides with terminal structures resembling human gangliosides GM1 and GD1a. High-molecular-weight molecules that reflected the presence of O chains were shown in immunoblots to be immunologically specific for each serostrain. The O:19 antiserum also reacted strongly with core oligosaccharides of two isolates from patients with Guillain-Barré syndrome (GBS), but the banding patterns and molecular structures were different from those of the O:19 serostrain. A neuraminobiose disaccharide unit is attached to the terminal Gal residue in one isolate, and the other isolate lacked terminal N-acetyl glucosamine and galactose with attached sialic acid so that the sialic acid residues were present in a neuraminobiose unit linked to the only remaining galactose. Analysis of the high-M(r) lipopolysaccharides of the O:19 serostrain and the two isolates from GBS patients revealed the presence of a hyaluronic acid-like polymer with disaccharide-repeating units consisting of beta-D-glucuronic acid amidated with 2-amino-2-deoxyglycerol and N-acetyl glucosamine. The results confirm a potential role for the core oligosaccharides in the etiology of GBS but also suggest that the O-chain polysaccharide may be a contributing factor.

Lipopolysaccharides of Campylobacter jejuni serotype O:19: structures of core oligosaccharide regions from the serostrain and two bacterial isolates from patients with the Guillain-Barré syndrome.

Lipopolysaccharides from phenol-water extraction of cells of Campylobacter jejuni serotype O:19 were separated into a water-soluble gel of low M(r) and a water-soluble component of high M(r). Acetic acid hydrolysis of the ketosidic linkages to lipid A furnished respectively a core oligosaccharide, the structure of which is reported herein, and an O antigenic polysaccharide. Structural investigations were performed on the O-deacetylated lipopolysaccharide of low M(r), the liberated core oligosaccharide and the various products from removal of neuraminic acid and phosphate residues, and from the Smith degradation. It is concluded that the lipopolysaccharide from the serostrain has a core region with two types of closely related oligosaccharide chains showing striking homologies with gangliosides, the first with a single N-acetylneuraminic acid residue in an outer chain resembling GM1 and the second with two N-acetyl-neuraminic acid residues with a terminal region resembling GD1a. Similar experiments were carried out on lipopolysaccharides of low M(r) from bacterial isolates OH 4384 and OH 4382 serotyped as O:19 that had been obtained from two patients who subsequently developed the Guillain-Barré syndrome. The core oligosaccharide region of lipopolysaccharide from the former isolate differed only slightly from that of the serostrain, whereas that from the latter isolate was distinctly shorter.

An antigenic polysaccharide from Campylobacter coli serotype O:30. Structure of a teichoic acid-like antigenic polysaccharide associated with the lipopolysaccharide.

A water-soluble antigenic polysaccharide of high M(r) associated with the lipopolysaccharide has been isolated from phenol-water extraction of cells of Campylobacter coli serotype O:30. The polysaccharide and oligosaccharide degradation products formed on O-dephosphorylation and by periodate oxidation followed by reduction have been investigated by one- and two-dimensional 1H, 13C, and 31P NMR. It is concluded that the antigenic polysaccharide has a teichoic acid-like structure with a poly-Ribitol phosphate, [5-Ribitol-1-P]n, backbone with side chains at O-2 of O-(6-deoxy-beta-D-talo-heptopyranosyl)-(1-->4)-(2-acetylamino-2-deoxy-beta-D- glucopyranosyl) units. The structure is unusual in Gram-negative bacteria and is unique in possessing 6-deoxy-D-talo-heptose as a constituent sugar. Evidence for the relationship of the antigenic polysaccharide to the lipopolysaccharide of low M(r) is discussed.

Chemical structure of the core region of Campylobacter jejuni serotype O:2 lipopolysaccharide.

The complete structure for the core region of Campylobacter jejuni serotype O:2 lipopolysaccharide (LPS) was assigned through studies on derivatives of the liberated oligosaccharide (OS 2) and the intact LPS. Structure determinations were performed using 1H-NMR spectroscopy, methylation studies supported by fast-atom-bombardment mass spectrometry and linkage analysis by gas chromatography/mass spectrometry, Smith degradation, and oxidation with chromium trioxide. It was concluded that complete oligosaccharide chains had the following structure: [formula: see text]

Lipopolysaccharide of Campylobacter coli serotype O:30. Fractionation and structure of liberated core oligosaccharide.

Lipopolysaccharide from phenol-water extraction of cells of Campylobacter coli serotype O:30 was separated as a water-insoluble gel of low M(r) from a water-soluble antigenic polysaccharide of high M(r). Acetic acid hydrolysis of the ketosidic linkages to lipid A in the lipopolysaccharide furnished a core oligosaccharide. Structural investigations were performed using 1H and 13C NMR, fast atom bombardment-mass spectrometry of permethylated derivatives, and methylation linkage analysis on the core oligosaccharide and the products of two successive Smith degradations. It is concluded that the highly branched 3-deoxy-D-manno-octulosonic acid-terminated oligosaccharide chains carried at the nonreducing end disaccharide units of beta-D-Qui3NAc-(1-->2)-beta-D-Qui3NAc (where Qui3NAc represents 3-acylamino-3,6-dideoxy-D-glucose), in which N-acyl residues were either both (R)-3-hydroxybutanoyl or both 3-hydroxy-2,3-dimethyl-5-oxoprolyl. The demonstration of these unusual features provides further evidence for a wide variety of structures within the core oligosaccharide region of lipopolysaccharides from Campylobacter sp.

Antigenicity of Helicobacter pylori lipopolysaccharides.

An investigation of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles of lipopolysaccharides (LPSs) extracted from seven strains of Helicobacter pylori revealed that these molecules were silver stainable and exhibited a high degree of variability in their patterns. Two strains synthesized a variety of sizes of LPS molecules such that fractionation by SDS-PAGE resulted in a stepwise gradation of bands which extended from the top to the bottom of the silver-stained gel. The LPSs from the remaining five strains were made up of molecules which were more homogeneous in size and clustered around two separate areas of the gel. Antigenic analyses of phenol-water-extracted LPSs by immunoblotting and the passive hemagglutination assay suggested that, in addition to strain-specific antigens, all of the LPSs carried a common antigen. Antibodies to this common antigen could be removed from antisera by absorption, and the resulting antisera were used to differentiate strains on the basis of their O antigens by the passive hemagglutination assay technique. The finding that LPSs from 3 of 10 clinical isolates reacted specifically in one or two of the typing antisera suggested that the development of a scheme for differentiating H. pylori on the basis of O antigens is feasible.

Variation of the O antigen of Campylobacter jejuni in vivo.

During the course of a clinical study on patients with campylobacteriosis, three consecutive isolates of Campylobacter jejuni from the same patient were sent for O-serotyping. Marked differences in the specificities of the O antigens of the isolates were observed between the first and third isolates when a passive haemagglutination assay system developed for serotyping C. jejuni was used. Differences in specificity were also demonstrated by immunoblots of lipopolysaccharides (LPS) from proteinase K-digested whole cells. The three isolates could not be distinguished either by restriction endonuclease analysis of chromosomal DNA, by gel electrophoresis of whole-cell proteins or by silver-stained LPS gels, thus providing evidence that they were of the same strain and that antigenic variation had occurred in vivo.

Serological diversity and chemical structures of Campylobacter jejuni low-molecular-weight lipopolysaccharides.

Low-Mr lipopolysaccharides (LPS) of Campylobacter jejuni reference strains for serotypes O:1, O:4, O:23, and O:36 were examined through the liberation of core oligosaccharides by mild acid cleavage of the ketosidic linkage of 3-deoxy-D-manno-2-octulosonic acid residues to the lipid A moiety. The liberated oligosaccharides were examined for chemical structure by compositional analysis and methylated linkage analysis in conjunction with fast atom bombardment-mass spectrometry of permethylated oligosaccharide derivatives. The results showed (i) that the LPS contained short oligosaccharide chains of branched nonrepetitive structure, to many of which N-acetylneuraminic acid residues remained attached by 2----3 linkages to 4-linked D-galactose residues in the core structure; (ii) that serotypical differences, which are not readily defined through qualitatively similar compositions, are clearly reflected in variations in linkage types and sequences of sugar residues in the outer core attached to an inner region of invariable structure; but (iii) that the presence or absence of NeuAc residues does not appear to be a basis for serotypical differences. The results also showed that oligosaccharide chains from LPS of serotypes O:1 and O:4 are distinctly different and are distinct again from those of the cross-reacting serotypes O:23 and O:36, between whose core oligosaccharide chains no differences were found. It is concluded that the structurally variable low-Mr LPS from C. jejuni show greater similarities to the lipooligosaccharides from Neisseria spp. than to the highly conserved core regions of Salmonella species. Those strains (serotypes O:23 and O:36) which also furnish high-Mr LPS are unique among gram-negative bacteria in possessing both low-Mr molecules of the Neisseria lipooligosaccharide type and high-Mr LPS of the Salmonella smooth type.

Antigenic shifts in serotype determinants of Campylobacter coli are accompanied by changes in the chromosomal DNA restriction endonuclease digestion pattern.

Changes in somatic (O) lipopolysaccharide (LPS) antigenic specificities of Campylobacter coli serostrains were observed after continuous laboratory subculture. Two serostrains (C. coli O34 and C. coli O48) lost O specificity and did not react with homologous or any of the available heterologous antisera. The C. coli serostrain for serogroup O5, after subculture, yielded a variant that had acquired a new specificity which was detectable with a heterologous antiserum. In a repeat experiment with the original isolate of the O5 strain, a second variant was obtained which had not only acquired the same new determinant but had, unlike the first variant, lost reactivity with the homologous antiserum. Immunoblot experiments with homologous and heterologous antisera indicated that changes in antigenic specificity were associated with the O side chains of the LPS molecules. Results of restriction endonuclease analysis of chromosomal DNA of the variants and their parents revealed minor differences in restriction patterns which suggested that C. coli is capable of undergoing genomic re-arrangements that lead to changes in LPS specificity and structure.

Identification of an antigen common to different species of the genus Campylobacter.

Affinity-purified antibody specific for a determinant on flagellin from Campylobacter jejuni was used to screen by immunoblotting strains of C. coli, C. laridis, C. fetus, "C. upsaliensis," C. pylori, and C. sputorum biovar fecalis. The antigen was detected in each of these species, but the molecular weights of the proteins bearing the common antigen varied considerably.

Amplified ELISA for the detection of western equine encephalitis virus from mosquitoes in Manitoba, Canada.

Current monitoring systems to detect western equine encephalitis (WEE) virus in mosquitoes involve isolation in suckling mice or cell culture followed by serological identification of the isolates obtained. Studies were undertaken to develop an amplified ELISA for the rapid detection of WEE virus from mosquitoes. Virus was inoculated onto primary chick embryo cells in 96 well plates, incubated at 37 degrees C for various time periods, monolayers were fixed, and an ELISA performed. By this procedure, 10 plaque-forming units or greater of WEE virus were detected by 24 h postinfection. This amplified ELISA procedure was successfully applied in parallel with standard isolation methods to monitor mosquitoes collected in Manitoba, Canada, in 1985 for WEE virus.