Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Microimmunofluorescence and Western immunoblotting were compared with the classical complement fixation reaction and the Weil-Felix test to study the serological responses of patients to Rickettsia prowazekii and both Proteus vulgaris OX19 and OX2 during primary and recrudescent typhus infections. The serological response to R. prowazekii was found to be similar during primary and recrudescent typhus, and all sera examined contained antibodies to the same R. prowazekii cell structures. Immunoglobulin G (IgG) and IgM were found to be the dominant anti-R. prowazekii immunoglobulins in all sera tested and were found to be directed against the 100-kDa protein and the lipopolysaccharide. IgA antibodies, when present, were mainly against the 100-kDa protein. For P. vulgaris, IgG antibodies recognized the proteins and lipopolysaccharides of both OX19 and OX2 serotypes; IgM antibodies were directed against the P. vulgaris OX2 lipopolysaccharide. In addition, donor blood sera, which were negative by microimmunofluorescence, were found to contain IgG immunoglobulins reacting with R. prowazekii protein antigens of 135, 60, and 47 kDa by western immunoblotting.
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PMID:Serological response of patients suffering from primary and recrudescent typhus: comparison of complement fixation reaction, Weil-Felix test, microimmunofluorescence, and immunoblotting. 749 69

Based on monosaccharide analysis and 1H- and 13C-NMR spectroscopy, the following structure of the O-specific polysaccharide chain of Proteus vulgaris OX2 lipopolysaccharide (LPS), which defines the O2 specificity of Proteus, was established: [formula: see text] where L-QuiNAc is N-acetyl-L-quinovosamine (2-acetamido-2,6-dideoxy-L-glucose). Various strains of P. vulgaris OX2 used in the Weil-Felix test for serodiagnosis of rickettsiosis (spotted fevers, except for Rocky Mountain spotted fever) were shown to produce LPS with the same O-specific polysaccharide, which differs structurally and serologically from LPS of P. vulgaris OX19 used as antigen for serodiagnosis of typhus and Rocky Mountain spotted fever. O-Acetyl groups present in the polysaccharide are not important for manifesting the immunospecificity. ELISA confirmed that the epitope responsible for the cross-reactivity between sera from patients with Japanese spotted fever and P. vulgaris OX2 cells is located on the P. vulgaris LPS. At the same time, no cross-reaction was observed between rabbit anti-P. vulgaris OX2 antibodies and the spotted fever group (SFG) rickettsial cells. Therefore, human anti-SFG rickettsial antibodies and rabbit anti-P. vulgaris OX2 antibodies may bind to distinct epitopes on P. vulgaris OX2 LPS, and no epitope recognized by rabbit anti-P. vulgaris OX2 antibodies is present on the LPS or any other surface antigen of SFG rickettsiae.
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PMID:Structural and serological studies of the O-antigen of the bacterium Proteus vulgaris OX2 (serogroup O2) used in the Weil-Felix test. 911 24

Sugar analysis and 1H- and 13C-NMR spectroscopic studies showed that various strains of Proteus mirabilis OXK used as antigens in the Weil-Felix test for serodiagnosis of rickettsiosis (scrub typhus) produce lipopolysaccharides (LPSs) with the same O-specific polysaccharide chain having the following structure: [formula: see text] where GlcA and GalA are glucuronic and galacturonic acids, respectively. This polysaccharide which defines the O3 specificity of Proteus and has been found earlier in an unclassified P. mirabilis strain S1959, contains an amide of D-galacturonic acid with L-lysine which plays an important role in manifesting the immunospecificity. A cross-reaction was observed in ELISA between sera from patients with scrub typhus, caused by the bacterium Orientia (Rickettsia) tsutsugamushi, and purified LPS of P. mirabilis OXK, thus suggesting that the common epitope involved in the Weil-Felix test is located on P. mirabilis OXK LPS. Rabbit anti-P. mirabilis OXK antibodies did not cross-react with LPS-lacking O. tsutsugamushi strain Gilliam in dot-blotting and Western blotting, and the nature of the rickettsial antigen responsible for the Weil-Felix reaction remains unknown.
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PMID:Structural and serological studies of the O-antigen of the bacterium Proteus mirabilis OXK (serogroup O3) used in the Weil-Felix test. 911 25

The structure of the O-specific polysaccharide chain of Proteus vulgaris OX19 lipopolysaccharide which determines the O1 specificity of Proteus and is used in the Weil-Felix test for diagnostics of rickettsiosis was established. On the basis of 1H- and 13 C-NMR spectroscopy, including two-dimensional correlation spectroscopy (COSY), H-detected 1H, 13C heteronuclear multiple-quantum coherence (HMQC), and rotating-frame nuclear Overhauser effect spectroscopy (ROESY), it was found that the polysaccharide consists of branched pentasaccharide repeating units containing D-galactose, 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-galactose, and 2-acetamido-2,6-dideoxy-D-glucose (QuiNAc, two residues), which are connected to each other via a phosphate group (P): [formula: see text]. The polysaccharide is acid-labile, the glycosyl phosphate linkage being cleaved at pH 4.5 (70 degrees C) to give a phosphorylated pentasaccharide with a galactose residue at the reducing end. Structural analysis of the oligosaccharide and a product of its dephosphorylation with 48% hydrofluoric acid using 1H- and 13C-NMR spectroscopy and electrospray ionization mass spectrometry confirmed the structure of the polysaccharide.
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PMID:Structure of the acid-labile galactosyl phosphate-containing O-antigen of the bacterium Proteus vulgaris OX19 (serogroup O1) used in the Weil-Felix test. 927 85

The lipopolysaccharides (LPSs) isolated from typhus group (TG) rickettsiae Rickettsia typhi and Rickettsia prowazekii were characterized by chemical analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by silver staining. LPSs from two species of TG rickettsiae contained glucose, 3-deoxy-D-manno-octulosonic acid, glucosamine, quinovosamine, phosphate, and fatty acids (beta-hydroxylmyristic acid and heneicosanoic acid) but not heptose. The O-polysaccharides of these LPSs were composed of glucose, glucosamine, quinovosamine, and phosphorylated hexosamine. Resolution of these LPSs by their apparent molecular masses by SDS-PAGE showed that they have a common ladder-like pattern. Based on the results of chemical composition and SDS-PAGE pattern, we suggest that these LPSs act as group-specific antigens. Furthermore, glucosamine, quinovosamine, and phosphorylated hexosamine were also found in the O-polysaccharide of the LPS from Proteus vulgaris OX19 used in the Weil-Felix test, suggesting that they may represent the antigens common to LPSs from TG rickettsiae and P. vulgaris OX19.
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PMID:Structural properties of lipopolysaccharides from Rickettsia typhi and Rickettsia prowazekii and their chemical similarity to the lipopolysaccharide from Proteus vulgaris OX19 used in the Weil-Felix test. 948 76

In a Weil-Felix test, sera from patients infected with Rickettsia sp. agglutinate Proteus OX types of bacteria and Proteus lipopolysaccharide (LPS) are responsible for the cross-reaction. Data on the character of LPS of one of the OX group strains, Proteus vulgaris OX19, are contradictory, and it remained unclear whether it has an O-polysaccharide (OPS) and is thus LPS of the smooth type (S) or not (rough-type LPS). Our studies showed that P. vulgaris OX19 (strain PZH-24) produces a smooth-type LPS that contains a long-chain OPS, but it undergoes depolymerization during mild acid hydrolysis conventionally used for LPS delipidation and loses the serological activity. An elucidation of the complete structure of OPS demonstrated the presence of a glycosyl phosphate linkage responsible for the acid-lability of the polysaccharide chain. In ELISA, both IgM type antibodies in a Weil-Felix test with human anti-Rickettsia typhi sera and rabbit anti-P. vulgaris OX19 antibodies reacted with OPS. Rabbit antibodies did not inhibit the cross-reaction with human antibodies and thus bind to different epitopes.
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PMID:Serological studies of an acid-labile O-polysaccharide of Proteus vulgaris OX19 lipopolysaccharide using human and rabbit antibodies. 985 61

In the Weil-Felix test, sera from patients infected with Orientia tsutsugamushi reacted with lipopolysaccharide (LPS) from Proteus mirabilis OXK strains. The O-polysaccharide of P. mirabilis OXK LPS consisted of pentasaccharide repeating units, with amidically-linked lysine residues. The lysine, linked to galacturonic residues, which plays an important role in the reaction with rabbit anti-OXK antibodies, was revealed with the aid of synthetic antigens. Using ELISA, immunoglobulin M antibodies from scrub typhus patients reacted with the O-specific polysaccharide of strain OXK LPS only. This reaction was inhibited by rabbit antibodies specific to the O-antigen of strain OXK LPS. Both human and rabbit antibodies may bind to similar epitopes on the O-polysaccharide part of P. mirabilis OXK LPS.
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PMID:Human anti-scrub typhus rickettsia and rabbit anti-Proteus antibodies recognize similar epitope in the O-polysaccharide part of Proteus mirabilis OXK lipopolysaccharide. 1113 8

Rickettsial diseases have long been diagnosed with serum antibodies cross-reactive against Proteus vulgaris (Weil-Felix reaction). Although Weil-Felix antibodies are associated with the development of immunity, their rickettsial target and contribution to disease pathogenesis are not established. Here, we developed a transposon for insertional mutagenesis of Rickettsia conorii, isolating variants defective for replication in cultured cells and in spotted fever pathogenesis. Mutations in the polysaccharide synthesis operon (pso) abolish lipopolysaccharide O-antigen synthesis and Weil-Felix serology and alter outer-membrane protein assembly. Unlike wild-type R. conorii, pso mutants cannot elicit bactericidal antibodies that bind O antigen. The pso operon is conserved among rickettsial pathogens, suggesting that bactericidal antibodies targeting O antigen may generate universal immunity that could be exploited to develop vaccines against rickettsial diseases.
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PMID:Rickettsia conorii O antigen is the target of bactericidal Weil-Felix antibodies. 3153 Jul 26