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Medical Microbiology and Immunology

, Volume 187, Issue 4, pp 205–212 | Cite as

Expression of interferon regulatory factors and indoleamine 2,3-dioxygenase in Chlamydia trachomatis-infected synovial fibroblasts

  • J. Rödel
  • Annemarie Groh
  • Matthias Hartmann
  • Karl-Hermann Schmidt
  • Marc Lehmann
  • Wolfgang Lungershausen
  • Eberhard Straube
ORIGINAL INVESTIGATION

Abstract

Synovial fibroblasts probably represent host cells for Chlamydia trachomatis during initial intra-articular infection in reactive arthritis. In vitro synovial cells produce interferon-β (IFN-β) in response to chlamydial infection. IFN-β expression can be activated by interferon regulatory factor-1 (IRF-1) and interferon-stimulated gene factor 3γ (ISGF3γ). In this study, we demonstrate that infection of synovial fibroblasts with C. trachomatis serotype D induced the expression of IRF-1 mRNA as shown by reverse transcription-PCR. Tumor necrosis factor-α (TNF-α) stimulation enhanced IRF-1 mRNA levels in infected cells and was required to detect IRF-1 protein by immunoblotting. The level of constitutively expressed IRF-2 was not significantly affected after infection. C. trachomatis was found to cause an up-regulation of ISGF3γ protein in synovial cells. Induction of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) is an important mechanism of the host cell response to control intracellular infection by chlamydiae. It has been described that IRF-1 can induce IDO gene expression. Infection of synovial fibroblasts alone in the absence of exogenous cytokine induced the expression of IDO mRNA which was enhanced by TNF-α treatment. The stimulation of IRF-1, ISGF3γ, and IDO expression was most effective when viable chlamydiae were used as inoculum. Neutralization of IFN-β in the culture medium of infected cells diminished but did not abrogate expression of IRF-1, ISGF3γ, and IDO. The increased production of IRF-1 and ISGF3γ in C. trachomatis-infected synovial fibroblasts may contribute to induction of IFN-β and IDO.

Key wordsChlamydia trachomatis Fibroblasts Interferon regulatory factor Interferon-stimulated gene factor 3γ Indoleamine 2 3-dioxygenase 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • J. Rödel
    • 1
  • Annemarie Groh
    • 1
  • Matthias Hartmann
    • 1
  • Karl-Hermann Schmidt
    • 1
  • Marc Lehmann
    • 1
  • Wolfgang Lungershausen
    • 2
  • Eberhard Straube
    • 1
  1. 1.Institute of Medical Microbiology, Friedrich Schiller University of Jena, Semmelweisstrasse 4, D-07743 Jena, Germany e-mail: Roedel@bach.med.uni-jena.de, Tel.: +49-3641-933105, Fax: +49-3641-933474DE
  2. 2.Clinic of Surgery, Friedrich Schiller University of Jena, Bachstr. 18, 07743 Jena, GermanyDE

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