Type I Interferons Direct Gammaherpesvirus Host Colonization

PLoS Pathog. 2016 May 25;12(5):e1005654. doi: 10.1371/journal.ppat.1005654. eCollection 2016 May.

Abstract

Gamma-herpesviruses colonise lymphocytes. Murid Herpesvirus-4 (MuHV-4) infects B cells via epithelial to myeloid to lymphoid transfer. This indirect route entails exposure to host defences, and type I interferons (IFN-I) limit infection while viral evasion promotes it. To understand how IFN-I and its evasion both control infection outcomes, we used Mx1-cre mice to tag floxed viral genomes in IFN-I responding cells. Epithelial-derived MuHV-4 showed low IFN-I exposure, and neither disrupting viral evasion nor blocking IFN-I signalling markedly affected acute viral replication in the lungs. Maximising IFN-I induction with poly(I:C) increased virus tagging in lung macrophages, but the tagged virus spread poorly. Lymphoid-derived MuHV-4 showed contrastingly high IFN-I exposure. This occurred mainly in B cells. IFN-I induction increased tagging without reducing viral loads; disrupting viral evasion caused marked attenuation; and blocking IFN-I signalling opened up new lytic spread between macrophages. Thus, the impact of IFN-I on viral replication was strongly cell type-dependent: epithelial infection induced little response; IFN-I largely suppressed macrophage infection; and viral evasion allowed passage through B cells despite IFN-I responses. As a result, IFN-I and its evasion promoted a switch in infection from acutely lytic in myeloid cells to chronically latent in B cells. Murine cytomegalovirus also showed a capacity to pass through IFN-I-responding cells, arguing that this is a core feature of herpesvirus host colonization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Disease Models, Animal
  • Enzyme-Linked Immunosorbent Assay
  • Gammaherpesvirinae / immunology
  • Gammaherpesvirinae / pathogenicity
  • Herpesviridae Infections / immunology*
  • Herpesviridae Infections / virology*
  • Humans
  • Immune Evasion / immunology*
  • Immunohistochemistry
  • Interferon Type I / immunology*
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Polymerase Chain Reaction
  • RAW 264.7 Cells

Substances

  • Interferon Type I

Grants and funding

The work was funded by: National Health and Medical Research Council (Australia) (www.nhmrc.gov.au), project grants 1060138, 1064015, 1079180 to PGS; Australian Research Council (www.arc.gov.au), Future Fellowship FT130100138 to PGS; Belspo (www.belspo.be), collaborative grant belvir to PGS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.