Ebola virus-like particles stimulate type I interferons and proinflammatory cytokine expression through the toll-like receptor and interferon signaling pathways

J Interferon Cytokine Res. 2014 Feb;34(2):79-89. doi: 10.1089/jir.2013.0035. Epub 2013 Oct 8.

Abstract

Ebola viruses (EBOV) can cause severe hemorrhagic disease with high case fatality rates. Currently, no vaccines or therapeutics are approved for use in humans. Ebola virus-like particles (eVLP) comprising of virus protein (VP40), glycoprotein, and nucleoprotein protect rodents and nonhuman primates from lethal EBOV infection, representing as a candidate vaccine for EBOV infection. Previous reports have shown that eVLP stimulate the expression of proinflammatory cytokines in dendritic cells (DCs) and macrophages (MΦs) in vitro. However, the molecular mechanisms and signaling pathways through which eVLP induce innate immune responses remain obscure. In this study, we show that eVLP stimulate not only the expression of proinflammatory cytokines but also the expression of type I interferons (IFNs) and IFN-stimulated genes (ISGs) in murine bone marrow-derived DCs (BMDCs) and MΦs. Our data indicate that eVLP trigger host responses through toll-like receptor (TLR) pathway utilizing 2 distinct adaptors, MyD88 and TRIF. More interestingly, eVLP activated the IFN signaling pathway by inducing a set of potent antiviral ISGs. Last, eVLP and synthetic adjuvants, Poly I:C and CpG DNA, cooperatively increased the expression of cytokines and ISGs. Further supporting this synergy, eVLP when administered together with Poly I:C conferred mice enhanced protection against EBOV infection. These results indicate that eVLP stimulate early innate immune responses through TLR and type I IFN signaling pathways to protect the host from EBOV infection.

Publication types

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

MeSH terms

  • Adaptor Proteins, Vesicular Transport / genetics
  • Adaptor Proteins, Vesicular Transport / metabolism
  • Animals
  • Cells, Cultured
  • Cytokines / metabolism
  • Dendritic Cells / immunology*
  • Dendritic Cells / virology
  • Ebolavirus / immunology*
  • Hemorrhagic Fever, Ebola / immunology*
  • Hemorrhagic Fever, Ebola / prevention & control
  • Humans
  • Immunity, Innate / drug effects
  • Inflammation Mediators / metabolism
  • Interferon Type I / metabolism
  • Macrophages / immunology*
  • Macrophages / virology
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Myeloid Differentiation Factor 88 / genetics
  • Myeloid Differentiation Factor 88 / metabolism
  • Poly I-C / administration & dosage
  • Primates
  • Rats
  • Receptor, Interferon alpha-beta / genetics
  • Receptor, Interferon alpha-beta / metabolism
  • Signal Transduction
  • Toll-Like Receptors / metabolism
  • Vaccines, Virus-Like Particle*
  • Virion / immunology*

Substances

  • Adaptor Proteins, Vesicular Transport
  • Cytokines
  • Ifnar1 protein, mouse
  • Inflammation Mediators
  • Interferon Type I
  • Myeloid Differentiation Factor 88
  • TICAM-1 protein, mouse
  • Toll-Like Receptors
  • Vaccines, Virus-Like Particle
  • Receptor, Interferon alpha-beta
  • Poly I-C