The roles of IRF-3 and IRF-7 in innate antiviral immunity against dengue virus

J Immunol. 2013 Oct 15;191(8):4194-201. doi: 10.4049/jimmunol.1300799. Epub 2013 Sep 16.

Abstract

We investigated the roles of IFN regulatory factor (IRF)-3 and IRF-7 in innate antiviral immunity against dengue virus (DENV). Double-deficient Irf-3(-/-)7(-/-) mice infected with the DENV2 strain S221 possessed 1,000-150,000 fold higher levels of viral RNA than wild-type and single-deficient mice 24 h postinfection (hpi); however, they remained resistant to lethal infection. IFN-α/β was induced similarly in wild-type and Irf-3(-/-) mice post-DENV infection, whereas in the Irf-7(-/-) and Irf-3(-/-)7(-/-) mice, significantly low levels of IFN-α/β expression was observed within 24 hpi. IFN-stimulated gene induction was also delayed in Irf-3(-/-)7(-/-) mice relative to wild-type and single-deficient mice. In particular, Cxcl10 and Ifnα2 were rapidly induced independently of both IRF-3 and IRF-7 in the Irf-3(-/-)7(-/-) mice with DENV infection. Higher levels of serum IFN-γ, IL-6, CXCL10, IL-8, IL-12 p70, and TNF were also observed in Irf-3(-/-)7(-/-) mice 24 hpi, at which time point viral titers peaked and started to be cleared. Ab-mediated blockade experiments revealed that IFN-γ, CXCL10, and CXCR3 function to restrict DENV replication in Irf-3(-/-)7(-/-) mice. Additionally, the IFN-stimulated genes Cxcl10, Ifit1, Ifit3, and Mx2 can be induced via an IRF-3- and IRF-7-independent pathway that does not involve IFN-γ signaling for protection against DENV. Collectively, these results demonstrate that IRF-3 and IRF-7 are redundant, albeit IRF-7 plays a more important role than IRF-3 in inducing the initial IFN-α/β response; only the combined actions of IRF-3 and IRF-7 are necessary for efficient control of early DENV infection; and the late, IRF-3- and IRF-7-independent pathway contributes to anti-DENV immunity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Aedes
  • Animals
  • Carrier Proteins / metabolism
  • Cell Line
  • Chemokine CXCL10 / biosynthesis
  • Chemokine CXCL10 / blood
  • Chemokine CXCL10 / immunology
  • Dengue / immunology*
  • Dengue Virus / immunology*
  • Immunity, Innate*
  • Interferon Regulatory Factor-3 / deficiency
  • Interferon Regulatory Factor-3 / genetics
  • Interferon Regulatory Factor-3 / metabolism*
  • Interferon Regulatory Factor-7 / deficiency
  • Interferon Regulatory Factor-7 / genetics
  • Interferon Regulatory Factor-7 / metabolism*
  • Interferon-alpha / blood*
  • Interferon-beta / blood*
  • Interferon-gamma / blood
  • Interferon-gamma / immunology
  • Interleukin-12 / blood
  • Interleukin-6 / blood
  • Interleukin-8 / blood
  • Intracellular Signaling Peptides and Proteins
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myxovirus Resistance Proteins / metabolism
  • Proteins / metabolism
  • RNA, Viral / blood
  • RNA-Binding Proteins
  • Receptors, CXCR3 / immunology
  • Signal Transduction
  • Tumor Necrosis Factors / blood
  • Viral Load
  • Virus Replication / immunology

Substances

  • Adaptor Proteins, Signal Transducing
  • Carrier Proteins
  • Chemokine CXCL10
  • Cxcl10 protein, mouse
  • Cxcr3 protein, mouse
  • Ifit1 protein, mouse
  • Ifit3 protein, mouse
  • Interferon Regulatory Factor-3
  • Interferon Regulatory Factor-7
  • Interferon-alpha
  • Interleukin-6
  • Interleukin-8
  • Intracellular Signaling Peptides and Proteins
  • Irf3 protein, mouse
  • Irf7 protein, mouse
  • Mx2 protein, mouse
  • Myxovirus Resistance Proteins
  • Proteins
  • RNA, Viral
  • RNA-Binding Proteins
  • Receptors, CXCR3
  • Tumor Necrosis Factors
  • Interleukin-12
  • Interferon-beta
  • Interferon-gamma

Associated data

  • GEO/GSE49871