Checks and balances between human cytomegalovirus replication and indoleamine-2,3-dioxygenase

J Gen Virol. 2014 Mar;95(Pt 3):659-670. doi: 10.1099/vir.0.061994-0. Epub 2013 Dec 11.

Abstract

Despite a rigorous blockade of interferon-γ (IFN-γ) signalling in infected fibroblasts as a mechanism of immune evasion by human cytomegalovirus (HCMV), IFN-γ induced indoleamine-2,3-dioxygenase (IDO) has been proposed to represent the major antiviral restriction factor limiting HCMV replication in epithelial cells. Here we show that HCMV efficiently blocks transcription of IFN-γ-induced IDO mRNA both in infected fibroblasts and epithelial cells even in the presence of a preexisting IFN-induced antiviral state. This interference results in severe suppression of IDO bioactivity in HCMV-infected cells and restoration of vigorous HCMV replication. Depletion of IDO expression nonetheless substantially alleviated the antiviral impact of IFN-γ treatment in both cell types. These findings highlight the effectiveness of this IFN-γ induced effector gene in restricting HCMV productivity, but also the impact of viral counter-measures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cytomegalovirus / genetics
  • Cytomegalovirus / physiology*
  • Cytomegalovirus Infections / enzymology*
  • Cytomegalovirus Infections / genetics
  • Cytomegalovirus Infections / virology
  • Humans
  • Indoleamine-Pyrrole 2,3,-Dioxygenase / genetics*
  • Indoleamine-Pyrrole 2,3,-Dioxygenase / metabolism
  • Interferon-gamma / metabolism
  • Virus Replication*

Substances

  • Indoleamine-Pyrrole 2,3,-Dioxygenase
  • Interferon-gamma