Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

By crossed immunoelectrophoresis, 85 different antigens were demonstrated in sonicated preparations of Legionella pneumophila serogroup 1 (Lp1). The precipitin patterns of 82 anodic-migrating antigens were numbered and were designated the Lp1 reference system. Eleven antigens were stable to boiling, and seven of these were shown to be surface antigens. One heat-stable surface antigen (antigen no. 61) was highly reactive with limulus amoebocyte lysates and formed a precipitin resembling lipopolysaccharide. Serum from an isolation confirmed case of Lp1 infection and serogroup-specific rabbit antiserum reacted specifically with antigen no. 61, which was designated the serogroup-specific antigen. Normal human and rabbit sera commonly had antibodies to antigen no. 66 of the Lp1 reference system. This antigen is antigenically related to the "common antigen" of Pseudomonas aeruginosa.
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PMID:Crossed immunoelectrophoretic analysis of Legionella pneumophila serogroup 1 antigens. 684 Aug 45

Sera from patients suffering from Mediterranean spotted fever (i.e. an infection due to Rickettsia conorii) were studied by immunoblot to investigate cross-reactivity. A prevalence of IgM antibodies to Proteus OX 19, Proteus OX 2, to the Rickettsia typhus group, to Legionella pneumophila serovars 4 and 5, to L. bozemanii Wiga and to L. micdadei Tatlock was found. Western blot confirmed that the antibodies were directed against the lipopolysaccharide as demonstrated by proteinase K digestion of the antigens. Cross-adsorptions showed that there is a common cross-reacting epitope among L. bozemanii Wiga, R. typhi and Proteus OX 19 but cross-reacting antibodies to L. micdadei and OX 2 were distinct and independent. This IgM cross-reaction could lead to a misdiagnosis.
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PMID:Immunoblot cross-reactions among Rickettsia, Proteus spp. and Legionella spp. in patients with Mediterranean spotted fever. 754 Dec 70

For identification of lipopolysaccharide (LPS)-associated epitopes of Legionella pneumophila serogroup 1, LPS of strain Philadelphia 1 was investigated using monoclonal antibodies (MAbs). The O-specific chain of LPS is a homopolymer of 5-acetamidino-7-acetamido-8-O-acetyl-3,5,7,9-tetradeoxy-D-glycero- L-galacto- nonulosonic acid. At least four immunoaccessible epitopes were recognized by different MAbs on the intact LPS. After O-deacetylation of LPS, the reactivity of one of the MAbs (MAb 3/1) was lost, indicating thus that the corresponding epitope is associated with the 8-O-acetyl group. Since the reactivity pattern of the MAb 3/1 is identical with those of the MAb 2 which was considered as a virulence marker for serogroup 1, this epitope may be involved in mediating virulence in L. pneumophila. Four MAbs specific to strains of serogroup 1 other than the monoclonal subtype Philadelphia recognized epitopes on the O-deacetylated LPS of strain Philadelphia 1 and, therefore, the virulence-associated epitope blocks recognition of the immunodeterminants that are accessible on the intact LPS of the strains lacking this epitope.
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PMID:Molecular characterization of a virulence-associated epitope on the lipopolysaccharide of Legionella pneumophila serogroup 1. 754 61

Incubation of Legionella pneumophila Philadelphia 1 in normal human serum depleted of either classical-pathway component C1q or alternative-pathway component factor B resulted in activation of the complement system. Experiments focused on the role of the classical pathway in complement activation revealed that legionellae bound C1q independently of antibody. Purified preparations of L. pneumophila major outer membrane protein but not serogroup 1 lipopolysaccharide bound C1q independently of antibody. This suggests that antibody-independent binding of C1q by L. pneumophila can result in activation of the classical pathway in normal human serum and that major outer membrane protein may be a C1q acceptor on the L. pneumophila cell surface.
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PMID:Antibody-independent binding of complement component C1q by Legionella pneumophila. 759 Nov 61

Salmonellae possess the ability to adhere to and invade macrophages and in so doing trigger a number of intracellular events that are associated with cellular activation. As an initial approach to defining the mechanisms by which invasive salmonellae alter macrophage function, we have explored the impact of Salmonella infection on the production of human immunodeficiency virus (HIV) in U1 cells, a promonocytic cell line latently infected with the virus. Infection of U1 cells with a pathogenic strain of Salmonella enteritidis resulted in a marked induction of macrophage activation and HIV production. The stimulatory effect of salmonellae was mediated by signals other than lipopolysaccharide. Salmonella mutants with specific defects in invasion or intracellular survival were markedly less effective in the induction of HIV production. In contrast to S. enteritidis, strains of Yersinia enterocolitica, Legionella pneumophila, and Escherichia coli did not induce HIV production. However, all of these bacteria induced comparable levels of gene expression mediated by the HIV long terminal repeat. The results of this study are consistent with the notion that invasive salmonellae possess the ability to activate the macrophage by at least one mechanism that is not shared with several other species of gram-negative bacteria. Furthermore, the expression of this unique property is maximal with Salmonella strains that are not only invasive but also capable of prolonged survival within the macrophage. Our results indicate that the U1 cell line may be a very useful model system with which to examine the biochemical pathways by which internalized salmonellae modulate the activation state of the macrophage.
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PMID:Regulation of macrophage activation and human immunodeficiency virus production by invasive Salmonella strains. 772 90

A Legionella pneumophila strain (Jena-1) was isolated from a water sample collected from the hot water system of a scientific institution in Jena, Germany. Protein profile, ubiquinone and fatty acid content of the outer membrane were in accordance with those described for other Legionella pneumophila serogroups. DNA extracted from strain Jena-1 gave a positive amplification by using an L. pneumophila (mip)-specific commercially available PCR-kit confirming that the isolate belonged to the species L. pneumophila. Strain Jena-1 reacted with a monoclonal antibody specific for the major outer membrane protein of the species L. pneumophila and another one recognizing a lipopolysaccharide epitope of L. pneumophila serogroups 2-6, 8-10, and 12-15. Cross-absorption studies using absorbed and unabsorbed rabbit antisera to serogroups 1-15 and the newly isolated strain showed that strain Jena-1 cross-reacted mainly with serogroup 4, and to a lesser extent, with serogroups 5, 8, and 10. These cross-reactions could be removed by cross-absorption without significant effects on the homologous titres. It is concluded that strain Jena-1 represents a new serogroup of Legionella pneumophila.
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PMID:Isolation of a Legionella pneumophila strain serologically distinguishable from all known serogroups. 773 27

Immunological cross-reactions among Legionella species were investigated with sonicated, proteinase K-digested cell lysates. The antigens separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis were either analyzed for lipopolysaccharides (LPSs) by silver staining or transferred to nitrocellulose membranes for serological characterization with rabbit antibodies directed against Legionella pneumophila serogroups 1 and 5. When antiserum prepared against serogroup 5 was used to probe the LPSs from L. pneumophila serogroups 1 to 14, the antibodies recognized a common epitope harbored by all L. pneumophila serogroups but not by other Legionella species or by the gram-negative bacteria tested as controls. Hence, the serogroup 5 antiserum correctly identified all serogroups of L. pneumophila tested in the LPS immunoblot assay. Moreover, the silver-stained profiles of the isolated LPSs revealed characteristic patterns allowing the identification of the individual serogroups of L. pneumophila.
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PMID:Cross-reacting lipopolysaccharide antigens in Legionella pneumophila serogroups 1 to 14. 776 96

Thioglycolate-elicited murine macrophages from genetically susceptible A/J mice activated with lipopolysaccharide (LPS) and infected with Legionella pneumophila in vitro evince marked inhibition of intracellular growth of this bacterium. The mechanism of inhibition by LPS-activated macrophages in terms of replication of this intracellular pathogen is unclear. LPS activation of murine macrophages induced a downshift in transferrin receptor (TfR) expression and reduction in cellular iron content, and this was correlated with augmented intracellular growth of Legionella in the cells. When LPS-stimulated macrophages were first saturated with iron, partial reversion of L. pneumophila growth restriction was observed. However, an excess of exogenous L-tryptophan (Trp) did not reverse this growth inhibition, nor did supplementation of the macrophage culture medium with both iron and Trp. The antilegionella activity of the macrophages induced by LPS activation was independent of reactive oxygen intermediates (ROI), since the scavengers catalase, superoxide dismutase, mannitol, and thiourea had no effect on growth restriction. Likewise, notwithstanding the ability of LPS-activated macrophages to synthesize reactive nitrogen intermediates (RNI), which was inhibited by L-arginine analogs NG-monomethyl-L-arginine and L-aminoguanidine), as well as by incubation in arginine-free medium, their ability to inhibit the intracellular replication of L. pneumophila was not affected. Thus, we conclude that LPS-activated macrophages inhibit the intracellular growth of L. pneumophila partially by iron-dependent, Trp-independent, and ROI- and RNI-independent mechanisms. We also suggest that additional unknown mechanisms are involved, since complete reversion was not obtained.
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PMID:LPS inhibits the intracellular growth of Legionella pneumophila in thioglycolate elicited murine peritoneal macrophages by iron-dependent, tryptophan-independent, oxygen-independent, and arginine-independent mechanisms. 782 75

Currently recommended methods in Legionnaires' disease serology are based upon crude whole-cell antigenic preparations. To investigate whether purified antigens would perform better in a given diagnostic test for antibodies against Legionella pneumophila, we compared the performance of three antigenic preparations of L. pneumophila serogroup 1 consisting of outer membrane protein (OMP), flagellin (FLA), and lipopolysaccharide (LPS) to a sonic extract (SON) in indirect immunosorbent assay (ELISA) measuring both IgG, IgA, and IgM. The reactivity of sera from 20 patients with culture-verified Legionnaires' disease and sera from 12 patients with pneumonia and a diagnostic rise in titre by a microagglutination test (MA) was studied. Our results indicated that the SON IgA assay was the most sensitive test in both groups of patients. The LPS IgG and IgM assays, however, were the most specific tests, closely followed by the corresponding SON tests. By combining two individual assays, a maximum nosographic sensitivity of 85% could be obtained. Whereas no benefit of using purified outer membrane protein or flagella instead of a sonic extract in the indirect ELISAs was found, the LPS antigen provided a sensitive and specific alternative to the sonic extract.
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PMID:Performance of four different indirect enzyme-linked immunosorbent assays (ELISAs) to detect specific IgG, IgA, and IgM in Legionnaires' disease. 791 19

The chemical composition of lipopolysaccharides from Legionella erythra and Legionella oakridgensis was analysed. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed both lipopolysaccharides to have a smooth-type character. The polysaccharide part of both lipopolysaccharides contained D-mannose, D-glucose, D-glycero-D-mannoheptose, L-glycero-D-manno-heptose, 2-keto-3-deoxyoctonic acid, L-fucosamine, D-glucosamine, and glucosamine phosphate. In addition, L-rhamnose, glycerol phosphate, and glucose phosphate were identified in the polysaccharide part of L. erythra lipopolysaccharide. The main sugar identified in the lipid A part of both lipopolysaccharides, 2,3-diamino-2,3-dideoxy-D-glucose, was found to be substituted with a complex fatty acid composition including at least 16 different amide-linked 3-hydroxy fatty acids. Both lipopolysaccharides contained nonhydroxy fatty acids and the uncommon 27-oxo-octacosanoic acid, 29-oxotriacontanoic acid, and 27-hydroxyoctacosanoic acid. The lipopolysaccharide of L. oakridgensis also contained 29-hydroxytriacontanoic acid. The dioic long-chain acids heptacosane-1,27-dioic acid and nonacosane-1,29-dioic acid were only present in the lipopolysaccharide of L. erythra.
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PMID:Lipopolysaccharides of Legionella erythra and Legionella oakridgensis. 792 88


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