ISG15 deficiency and increased viral resistance in humans but not mice


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Speer S. D., Li Z., Buta S., Payelle-Brogard B., Qian L., Vigant F., ...More

NATURE COMMUNICATIONS, vol.7, 2016 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 7
  • Publication Date: 2016
  • Doi Number: 10.1038/ncomms11496
  • Journal Name: NATURE COMMUNICATIONS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Hacettepe University Affiliated: Yes

Abstract

ISG15 is an interferon (IFN)-alpha/beta-induced ubiquitin-like protein. It exists as a free molecule, intracellularly and extracellularly, and conjugated to target proteins. Studies in mice have demonstrated a role for Isg15 in antiviral immunity. By contrast, human ISG15 was shown to have critical immune functions, but not in antiviral immunity. Namely, free extracellular ISG15 is crucial in IFN-gamma-dependent antimycobacterial immunity, while free intracellular ISG15 is crucial for USP18-mediated downregulation of IFN-alpha/beta signalling. Here we describe ISG15-deficient patients who display no enhanced susceptibility to viruses in vivo, in stark contrast to Isg15-deficient mice. Furthermore, fibroblasts derived from ISG15-deficient patients display enhanced antiviral protection, and expression of ISG15 attenuates viral resistance to WT control levels. The species-specific gain-of-function in antiviral immunity observed in ISG15 deficiency is explained by the requirement of ISG15 to sustain USP18 levels in humans, a mechanism not operating in mice.