Hepatitis C virus pathogen associated molecular pattern (PAMP) triggers production of lambda-interferons by human plasmacytoid dendritic cells

PLoS Pathog. 2013;9(4):e1003316. doi: 10.1371/journal.ppat.1003316. Epub 2013 Apr 18.

Abstract

Plasmacytoid Dendritic Cells (pDCs) represent a key immune cell in the defense against viruses. Through pattern recognition receptors (PRRs), these cells detect viral pathogen associated molecular patterns (PAMPs) and initiate an Interferon (IFN) response. pDCs produce the antiviral IFNs including the well-studied Type I and the more recently described Type III. Recent genome wide association studies (GWAS) have implicated Type III IFNs in HCV clearance. We examined the IFN response induced in a pDC cell line and ex vivo human pDCs by a region of the HCV genome referred to as the HCV PAMP. This RNA has been shown previously to be immunogenic in hepatocytes, whereas the conserved X-region RNA is not. We show that in response to the HCV PAMP, pDC-GEN2.2 cells upregulate and secrete Type III (in addition to Type I) IFNs and upregulate PRR genes and proteins. We also demonstrate that the recognition of this RNA is dependent on RIG-I-like Receptors (RLRs) and Toll-like Receptors (TLRs), challenging the dogma that RLRs are dispensable in pDCs. The IFNs produced by these cells in response to the HCV PAMP also control HCV replication in vitro. These data are recapitulated in ex vivo pDCs isolated from healthy donors. Together, our data shows that pDCs respond robustly to HCV RNA to make Type III Interferons that control viral replication. This may represent a novel therapeutic strategy for the treatment of HCV.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Cell Line, Tumor
  • Culture Media, Conditioned
  • Dendritic Cells / immunology*
  • Dendritic Cells / metabolism
  • Hepacivirus / immunology*
  • Hepatitis C / immunology*
  • Humans
  • Interferon Type I / biosynthesis*
  • Interferons
  • Interleukins / biosynthesis
  • RNA Interference
  • RNA, Small Interfering
  • RNA, Viral / immunology
  • Receptors, Retinoic Acid
  • Toll-Like Receptors / metabolism
  • Virus Replication

Substances

  • Culture Media, Conditioned
  • interferon-lambda, human
  • Interferon Type I
  • Interleukins
  • PLAAT4 protein, human
  • RNA, Small Interfering
  • RNA, Viral
  • Receptors, Retinoic Acid
  • Toll-Like Receptors
  • Interferons