PLoS Pathogens (Sep 2017)

Interference with the production of infectious viral particles and bimodal inhibition of replication are broadly conserved antiviral properties of IFITMs.

  • Kevin Tartour,
  • Xuan-Nhi Nguyen,
  • Romain Appourchaux,
  • Sonia Assil,
  • Véronique Barateau,
  • Louis-Marie Bloyet,
  • Julien Burlaud Gaillard,
  • Marie-Pierre Confort,
  • Beatriz Escudero-Perez,
  • Henri Gruffat,
  • Saw See Hong,
  • Marie Moroso,
  • Olivier Reynard,
  • Stéphanie Reynard,
  • Elodie Decembre,
  • Najate Ftaich,
  • Axel Rossi,
  • Nannan Wu,
  • Frédérick Arnaud,
  • Sylvain Baize,
  • Marlène Dreux,
  • Denis Gerlier,
  • Glaucia Paranhos-Baccala,
  • Viktor Volchkov,
  • Philippe Roingeard,
  • Andrea Cimarelli

DOI
https://doi.org/10.1371/journal.ppat.1006610
Journal volume & issue
Vol. 13, no. 9
p. e1006610

Abstract

Read online

IFITMs are broad antiviral factors that block incoming virions in endosomal vesicles, protecting target cells from infection. In the case of HIV-1, we and others reported the existence of an additional antiviral mechanism through which IFITMs lead to the production of virions of reduced infectivity. However, whether this second mechanism of inhibition is unique to HIV or extends to other viruses is currently unknown. To address this question, we have analyzed the susceptibility of a broad spectrum of viruses to the negative imprinting of the virion particles infectivity by IFITMs. The results we have gathered indicate that this second antiviral property of IFITMs extends well beyond HIV and we were able to identify viruses susceptible to the three IFITMs altogether (HIV-1, SIV, MLV, MPMV, VSV, MeV, EBOV, WNV), as well as viruses that displayed a member-specific susceptibility (EBV, DUGV), or were resistant to all IFITMs (HCV, RVFV, MOPV, AAV). The swapping of genetic elements between resistant and susceptible viruses allowed us to point to specificities in the viral mode of assembly, rather than glycoproteins as dominant factors of susceptibility. However, we also show that, contrarily to X4-, R5-tropic HIV-1 envelopes confer resistance against IFITM3, suggesting that viral receptors add an additional layer of complexity in the IFITMs-HIV interplay. Lastly, we show that the overall antiviral effects ascribed to IFITMs during spreading infections, are the result of a bimodal inhibition in which IFITMs act both by protecting target cells from incoming viruses and in driving the production of virions of reduced infectivity. Overall, our study reports for the first time that the negative imprinting of the virion particles infectivity is a conserved antiviral property of IFITMs and establishes IFITMs as a paradigm of restriction factor capable of interfering with two distinct phases of a virus life cycle.