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Query: UNIPROT:P43026 (lipopolysaccharide)
 62,215 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cell surfaces of two Chlamydia trachomatis serovars were explored by immune electron microscopy with monoclonal antibodies that recognize a number of chlamydial outer-membrane components. Species, subspecies and serovar-reactive epitopes on the major outer-membrane protein (MOMP) of a lymphogranuloma venereum biovar strain, L2/434/Bu, and a trachoma biovar strain, F/UW-6/Cx, were exposed on the surfaces of both elementary bodies (EBs) and reticulate bodies (RBs). Three epitopes on MOMP were inaccessible on EBs and RBs of both strains. These included a genus-reactive, species-reactive, and a subspecies-reactive epitope. In contrast, genus-specific epitopes on lipopolysaccharide (LPS) were not detected on the EB surface, but were clearly expressed on RBs of both L2/434/Bu and F/UW-6/Cx chlamydiae. Antibodies specific for the 60 kDa and 12 kDa 'cysteine-rich' outer-membrane proteins did not react with surface epitopes on either EBs or RBs. These data provide evidence that MOMP is a major surface antigen of both morphological forms, whereas some portions of the LPS molecule are exposed on the RB surface but become inaccessible to antibody after conversion to the infectious EB form.
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PMID:Detection of surface-exposed epitopes on Chlamydia trachomatis by immune electron microscopy. 247 26

New biotechnology in immunology and molecular biology has enabled the identification and definition of the structure of glycolipids and especially membrane proteins of Chlamydia. Chlamydia antigen lipopolysaccharide, major outer membrane protein, protein 74 kDa, eukaryotic cell binding protein and cysteine rich proteins are all carriers of antigenic determinants, genus, species or type specific. They are very usefull for diagnosis of Chlamydial infections and epidemiological studies. These membranous antigens have an important role in the pathogenesis of these bacteries. Finally these studies have contributed to the isolation of a new species: C. pneumoniae (TWAR strains).
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PMID:[Biochemical characteristics and antigenic structures of Chlamydia]. 248 18

Interferon-gamma (IFN-gamma) previously has been shown to inhibit the replication of Chlamydia psittaci in epithelial cells by inducing indoleamine 2,3-dioxygenase, the enzyme that decyclizes tryptophan to N-formylkynurenine. The role of indoleamine 2,3-dioxygenase in IFN-mediated inhibition of C. psittaci in human macrophages has now been examined. Peripheral blood monocytes from normal donors were isolated and cultivated 10-14 days to allow differentiation to macrophages. Cells were then treated with either IFN-gamma or IFN-beta for 48 h before infection with sufficient C. psittaci to infect approximately 30% of the cells. Infected cells were incubated 24 h, at which time coverslips were fixed, stained with Giemsa, and examined for development of C. psittaci inclusions by light microscopy. Complete inhibition of inclusion development was observed with IFN-gamma. In the absence of lipopolysaccharide, inhibition of C. psittaci by IFN-beta was variable; however, in the presence of lipopolysaccharide, IFN-beta also completely inhibited C. psittaci replication. The addition of excess tryptophan to the culture medium at the time of infection partially reversed the effect of IFN on the inhibition of C. psittaci growth in a concentration-dependent manner. Indoleamine 2,3-dioxygenase activity was determined by measurement of the concentrations of tryptophan and its metabolites in the culture medium after reversed-phase high-performance liquid chromatography. Significant indoleamine 2,3-dioxygenase activity was observed only in macrophages treated with IFN-gamma or combined IFN-beta plus lipopolysaccharide, and resulted in greater than 50% of available tryptophan being catabolized in a 4-h period.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interferon-induced indoleamine 2,3-dioxygenase activity inhibits Chlamydia psittaci replication in human macrophages. 250 98

ATPase activity of elementary bodies (EBs) of Chlamydia trachomatis was investigated by using high-resolution 31P nuclear magnetic resonance spectroscopy. ATPase activity was detected in EBs of C. trachomatis serovars A, B, and L2 after treatment with the reducing agents 2-mercaptoethanol and glutathione. ATPase activity was oligomycin sensitive and magnesium ion dependent. EBs heated at 60 degrees C for 10 min or pretreated with Triton X-100 before exposure to 2-mercaptoethanol did not exhibit ATPase activity. Monoclonal antibody to the major outer membrane protein abrogated ATPase activity of EBs, whereas monoclonal antibody to chlamydial lipopolysaccharide only marginally reduced the level of ATPase activity. These findings suggest that EBs possess intrinsic ATPase activity and that cysteine-rich outer membrane proteins of EBs are important in the regulation of ATPase activity. The major outer membrane protein may be the major route through which ATP accesses ATPase.
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PMID:High-resolution 31P nuclear magnetic resonance study of Chlamydia trachomatis: induction of ATPase activity in elementary bodies. 253 Jan 75

The antigenic properties of the lipopolysaccharide (LPS) of Chlamydia trachomatis L2 were investigated. By means of passive hemolysis, passive hemolysis inhibition, and absorption experiments, it was shown that antiserum raised against chlamydial elementary bodies contained at least two different antibody specificities which reacted with different antigenic determinants of chlamydial LPS. One of these antibodies cross-reacted with enterobacterial Re LPS, recognizing a structure which is shared by both LPSs, whereas the reactivity of the second antibody was restricted to chlamydial LPS. The former antibody could be absorbed with Salmonella minnesota Re LPS, whereas the latter was not affected by this absorption. Therefore, chlamydial LPS possesses two distinct antigenic determinants, one of which is C. trachomatis specific, the other of which is responsible for the cross-reactivity with enterobacterial Re-type LPS. Both antigenic determinants were destroyed during mild acid-catalyzed hydrolysis. It was further shown that free chlamydial lipid A exhibits antigenicity that cross-reacts with free enterobacterial lipid A. This antigenicity, however, as in enterobacterial LPS, is present in a cryptic form, i.e., it is unmasked only after acid hydrolysis of LPS.
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PMID:Antigenic properties of Chlamydia trachomatis lipopolysaccharide. 258 Jul 95

The obligate intracellular prokaryote Chlamydia trachomatis is the etiological agent of trachoma and is a primary causative pathogen of sexually transmitted genital tract disease; both diseases affect millions of people each year. The cloning of genes encoding the enzyme or enzymes producing the genus-specific lipopolysaccharide antigen of Chlamydia into Escherichia coli is reported here. The cloned chlamydial lipopolysaccharide antigen appears to be a hybrid lipopolysaccharide molecule composed of both Chlamydia and Escherichia coli components. The chlamydial lipopolysaccharide antigen is expressed on the surfaces of the viable Escherichia coli recombinants. These findings may have a significant impact on defining the role of this highly conserved antigen in the pathogenesis and diagnosis of chlamydial infections.
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PMID:Expression of the chlamydial genus-specific lipopolysaccharide epitope in Escherichia coli. 258 15

Recent studies suggest that a group of Chlamydia strains known as TWAR, which are now proposed to be a new species called Chlamydia pneumoniae, may be a frequent cause of respiratory disease in the United States and many other countries. Current serotesting methods do not allow rapid screening of large numbers of samples to distinguish C. trachomatis exposure from C. pneumoniae exposure. We developed an enzyme immunoassay to decrease cross-reactivity between immunoglobulin G antibodies reactive with C. trachomatis and C. pneumoniae. Elementary bodies of C. trachomatis or C. pneumoniae were treated with a detergent-chelating solution to decrease the reactivity of the common lipopolysaccharide antigens. Sera from four groups of patients, totaling 143 persons, were tested by this assay. The prevalences of titers of greater than or equal to 128 to C. trachomatis and C. pneumoniae, respectively, were as follows: (i) for 23 women seropositive for C. trachomatis by the microimmunofluorescence test, 21 (91%) and 18 (78%); (ii) for 50 adult blood donors, 13 (26%) and 39 (78%); (iii) for 40 sexually transmitted disease clinic patients, 20 (50%) and 32 (80%); (iv) for 30 healthy children 5 to 7 years old, 0 (0%) and 8 (27%). Western blots (immunoblots) of each antigen corroborated the differential reactivity of C. trachomatis-positive, C. pneumoniae-negative and C. trachomatis-negative, C. pneumoniae-positive serum samples. Western blots of serum samples from rabbits immunized with either C. trachomatis or C. pneumoniae elementary bodies revealed at least two protein bands (30 and 80 kilodaltons) which appeared to represent unique C. pneumoniae antigens.
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PMID:Enzyme immunoassay to determine exposure to Chlamydia pneumoniae (strain TWAR). 259 40

The enzyme-amplified immunoassay IDEIA (CellTech Diagnostics), which measures lipopolysaccharide antigen, and Chlamydiazyme (Abbott Laboratories, North Chicago, Ill.), which measures several antigenic components of Chlamydia trachomatis, were compared for specimens from urethral swabs from 235 men attending a clinic for sexually transmitted diseases (culture prevalence of 14.9%) and 458 endocervical swabs from women attending planned parenthood and obstetrics-gynecology clinics (culture prevalences of 5.9 and 7.7%, respectively). Compared with cell culture, the percent sensitivites, specificities, and positive and negative predictive values for IDEIA were 62.5, 99.5, 95.2, and 94.3%, respectively, for specimens from men and 96.3, 97.9, 74.3, and 99.8%, respectively, for specimens from women; results for Chlamydiazyme for specimens from men were 81.8, 99.5, 96.4, and 97.1%, respectively, and for specimens from women, results were 85.2, 99.3, 88.5, and 99.1%, respectively. Although the specificities of IDEIA and Chlamydiazyme were comparable, the sensitivity of IDEIA appeared higher for women (96.3%) than for men (67.5%), while the sensitivities of Chlamydiazyme were similar for men (81.8%) and women (85.2%). Western blot (immunoblot) analysis of the detector reagents from the two immunoassays indicated that the differences in performance observed for the two immunoassays may be due to measurement of different antigens.
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PMID:Diagnosis of Chlamydia trachomatis genital infections by cell culture and two enzyme immunoassays detecting different chlamydial antigens. 267 91

We have developed an enzyme immunoassay to measure antibodies to the proteins and lipopolysaccharide (LPS) of Chlamydia trachomatis. Antibodies to proteins could be differentiated from antibodies to lipopolysaccharide (LPS) by treatment of the antigen with periodate or Triton X-100. Some important parameters of the oxidation by periodate were studied by comparing the response of several monoclonal antibodies. Four types of response could be observed: type I, a reduced response after mild or strong oxidation; type II, a normal response after mild oxidation, but reduced after strong oxidation; type III, not affected; type IV, an increased response after oxidation. Treatment with Triton X-100 had the same effect as mild oxidation and confirmed the response types I, III, and IV. Treatment of antigen with periodate reduced the IgG response measured in sera from patients with evidence of Chlamydia psittaci infection.
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PMID:An enzyme immunoassay to detect specific antibodies to protein and lipopolysaccharide antigens of Chlamydia trachomatis. 268 25

Monoclonal antibodies (MAb) specific for Chlamydia trachomatis lipopolysaccharide (LPS) and major outer membrane protein (MOMP) were used for immunoelectron microscopy analysis. MAb specific for MOMP showed strong reaction with the chlamydial surface, whereas MAb specific for LPS showed strong association of gold particles with the periphery of the chlamydial body. After fixation of the chlamydia cells, the reactivity was, however, similar to the anti-MOMP reactivity. Enzyme-linked immunosorbent assay showed that MAb specific for LPS could remove LPS from the chlamydial membrane.
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PMID:Immunoelectron microscopy of lipopolysaccharide in Chlamydia trachomatis. 277 84


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