Abstract:
:Ehrlichia chaffeensis, an obligatory intracellular bacterium of monocytes or macrophages, is the etiologic agent of human monocytic ehrlichiosis. Our previous study showed that gamma interferon (IFN-gamma) added prior to or at early stage of infection inhibited infection of human monocytes with E. chaffeensis; however, after 24 h of infection, IFN-gamma had no antiehrlichial effect. To test whether ehrlichial infection disrupts Janus kinase (Jak) and signal transducer and activator of transcription (Stat) signaling induced by IFN-gamma, tyrosine phosphorylation of Stat1, Jak1, and Jak2 in E. chaffeensis-infected THP-1 cells was examined by immunoprecipitation followed by immunoblot analysis. Viable E. chaffeensis organisms blocked tyrosine phosphorylation of Stat1, Jak1, and Jak2 in response to IFN-gamma within 30 min of infection. Similar results were obtained with human peripheral blood monocytes infected with E. chaffeensis. Heat or proteinase K treatment but not periodate treatment of E. chaffeensis abrogated the inhibitory effect, suggesting that protein factor(s) of E. chaffeensis is responsible for the inhibition of IFN-gamma-induced tyrosine phosphorylation. Preincubation of E. chaffeensis with the Fab fragment of dog anti-E. chaffeensis immunoglobulin G also abrogated the inhibitory effect. On the other hand, monodansylcadaverine, which does not block binding but blocks internalization of ehrlichiae into macrophages, did not have any influence on the tyrosine phosphorylation. These results indicate that ehrlichial binding to host cells is sufficient to inhibit Stat1 tyrosine phosphorylation induced by IFN-gamma. Protein kinase A (PKA) activity in THP-1 cells increased approximately 25-fold within 30 min of infection with E. chaffeensis. In THP-1 cells pretreated with a PKA inhibitor, Rp isomer of adenosine 3',5'-cyclic phosphorothioate, E. chaffeensis-induced inhibition of Stat1 tyrosine phosphorylation was partially abrogated. These results suggest that E. chaffeensis blocks IFN-gamma-induced tyrosine phosphorylation of Jak and Stat through raising PKA activity in THP-1 cells, which may be an important survival mechanism of ehrlichiae within the host cell.
journal_name
Infect Immunjournal_title
Infection and immunityauthors
Lee EH,Rikihisa Ydoi
10.1128/IAI.66.6.2514-2520.1998subject
Has Abstractpub_date
1998-06-01 00:00:00pages
2514-20issue
6eissn
0019-9567issn
1098-5522journal_volume
66pub_type
杂志文章abstract::Reduced-minus-oxidized difference spectra of sonically treated virulent Treponema pallidum disclosed cytochromes of the b anc c types as well as large amounts of flavoprotein. Difference spectra of the carbon monoxide-binding pigment identified cytochrome o as the terminal oxidase. Physiological reduction of the cytoc...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.16.3.885-890.1977
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abstract::Isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with acrylamide copolymerized with gelatin (substrate-SDS-PAGE) were combined to evaluate the proteinases of both long-term-grown and fresh isolates of Trichomonas vaginalis. This two-dimensional substrate-SDS-PAGE resolved a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.58.1.157-162.1990
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journal_title:Infection and immunity
pub_type: 杂志文章
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abstract::Bacteroides spp. may contribute to the chronicity of mixed infections by affecting the normal functions of polymorphonuclear leukocytes (PMN). This study evaluated the physiologic and biochemical responses of human peripheral blood PMN to a variety of strains of the oral periodontal pathogen Porphyromonas (Bacteroides...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.59.9.3134-3142.1991
更新日期:1991-09-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.22.1.57-61.1978
更新日期:1978-10-01 00:00:00
abstract::An LT-B-ST (LT-B/ST) fusion peptide was constructed by genetically joining the 5' terminus of a synthetic gene coding for the heat-stable enterotoxin (ST) of Escherichia coli to the 3' terminus of the gene coding for the binding subunit of the heat-labile enterotoxin (LT-B) of E. coli. An eight-amino-acid, proline-con...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.61.11.4629-4636.1993
更新日期:1993-11-01 00:00:00
abstract::Bordetella pertussis extract that contained adenylate cyclase toxin produced large increases in human neutrophil cyclic AMP levels and inhibited their oxidative burst, as reflected by luminol-enhanced chemiluminescence and superoxide release. The adenylate cyclase toxin-containing extract blocked neutrophil-mediated i...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.56.4.751-755.1988
更新日期:1988-04-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.45.2.518-521.1984
更新日期:1984-08-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.58.8.2696-2698.1990
更新日期:1990-08-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.41.2.858-860.1983
更新日期:1983-08-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.22.3.908-918.1978
更新日期:1978-12-01 00:00:00
abstract::We have developed sensitive and specific solid-phase radioimmunoassays to quantitate the distribution and persistence of bacterial antigen in rats developing arthritis in response to a single injection of streptococcal cell wall material. Three separate assays were specific for either the A polysaccharide (N-acetyl-D-...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.38.1.127-135.1982
更新日期:1982-10-01 00:00:00
abstract::The effector mechanism, which operates against challenge parasites in the lungs of C57BL/6 mice vaccinated once with irradiated cercariae of Schistosoma mansoni, is mediated by CD4+ T helper lymphocytes. However, adoptive transfer of immunity from vaccinated donors to naive recipients by using sensitized T cells has n...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.65.1.42-48.1997
更新日期:1997-01-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00700-09
更新日期:2009-12-01 00:00:00
abstract::Routine culture of endothelial cells currently includes the use of heparin, which significantly reduces cell doubling time and increases cell population size. Heparin protects cultured arterial endothelial cells from damage by toxic oxygen metabolites produced by the action of xanthine and xanthine oxidase. Because of...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.59.12.4505-4510.1991
更新日期:1991-12-01 00:00:00
abstract::Various invasive pathogens attach to host tissues via the extracellular matrix component laminin, the major glycoprotein found within basement membranes. Previous investigations identified the laminin-binding adhesin Tp0751 within the spirochete bacterium Treponema pallidum. In the current study, Tp0751 was shown to a...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.73.11.7485-7494.2005
更新日期:2005-11-01 00:00:00
abstract::Virulence of the fungal pathogen Aspergillus fumigatus is in part based on the saprophytic lifestyle that this mold has evolved. A crucial function for saprophytism resides in secreted proteases that allow assimilation of proteinaceous substrates. The impact of extracellular proteolytic activities on the pathogenesis ...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00425-09
更新日期:2009-09-01 00:00:00
abstract::Inflammatory cytokines play an important role in human immune responses to malarial disease. However, the role of these mediators in disease pathogenesis, and the relationship between host protection and injury remains unclear. A total of 248 cases of severe Plasmodium falciparum malaria among children aged 3 months t...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.72.10.5630-5637.2004
更新日期:2004-10-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.61.7.2872-2878.1993
更新日期:1993-07-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00409-18
更新日期:2019-07-23 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/iai.70.1.107-113.2002
更新日期:2002-01-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.47.2.555-560.1985
更新日期:1985-02-01 00:00:00
abstract::A gene encoding the cytotoxic enterotoxin (Act) from Aeromonas hydrophila was hyperexpressed with the pET, pTRX, and pGEX vector systems. Maximum toxin yield was obtained with the pTRX vector. Approximately 40 to 60% of Act was in a soluble form with the pTRX and pET vector systems. The toxin protein was purified to h...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.65.10.4299-4308.1997
更新日期:1997-10-01 00:00:00
abstract::C57BL/6 mice infected with Leishmania mexicana showed depression of the in vitro immunoglobulin M-plaque-forming cell response to sheep erythrocytes. Immunodepression was present 3 weeks after inoculation and was maximal at 11 weeks. Thereafter, there was a gradual return to normal immunoresponsiveness correlated with...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.32.2.415-419.1981
更新日期:1981-05-01 00:00:00
abstract::Macrophage recognition of Salmonella enterica serovar Typhimurium leads to a cascade of signaling events, including the activation of Src family and Syk kinases and the production of reactive oxygen species (ROS), which are critical for host innate defense during early stages of bacterial infection. ROS production dep...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.00115-08
更新日期:2008-06-01 00:00:00
abstract::A chemically defined medium developed for Neisseria gonorrhoeae was modified to support the growth of Campylobacter jejuni and Campylobacter coli. A total of 76 isolates of C. jejuni and 14 isolates of C. coli were tested on this medium, which was designated Campylobacter defined medium (CDM), over a 3-month period. A...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.48.2.384-388.1985
更新日期:1985-05-01 00:00:00
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journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.01138-07
更新日期:2008-02-01 00:00:00
abstract::Heterogeneic autoantibodies against axonal neurofilament proteins of mature mouse neurons grown in vitro were detected by the indirect immunofluorescence technique in 12.7% (9 of 71) of the sera from nonhuman primates infected with kuru, in 14.5% (17 of 117) and 4% (1 of 25), respectively, of the sera from nonhuman pr...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.38.1.316-324.1982
更新日期:1982-10-01 00:00:00
abstract::The initial encounter of Leishmania cells and cells from the immune system is fundamentally important in the outcome of infection and determines disease development or resistance. We evaluated the anti-Leishmania amazonensis response of naive volunteers by using an in vitro priming (IVP) system and comparing the respo...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.69.12.7453-7460.2001
更新日期:2001-12-01 00:00:00
abstract::Vesicular stomatitis virus (Indiana strain) will only grow in T lymphocytes which have been stimulated to undergo cell division. Evidence is presented that a considerable enrichment of the vesicular stomatitis virus-replicating T cells may be accomplished in the mouse spleen by passing the spleen cells over glass wool...
journal_title:Infection and immunity
pub_type: 杂志文章
doi:10.1128/IAI.32.1.169-172.1981
更新日期:1981-04-01 00:00:00