IL-15 complexes induce NK- and T-cell responses independent of type I IFN signaling during rhinovirus infection

Mucosal Immunol. 2014 Sep;7(5):1151-64. doi: 10.1038/mi.2014.2. Epub 2014 Jan 29.

Abstract

Rhinoviruses are among the most common viruses to infect man, causing a range of serious respiratory diseases including exacerbations of asthma and COPD. Type I IFN and IL-15 are thought to be required for antiviral immunity; however, their function during rhinovirus infection in vivo is undefined. In RV-infected human volunteers, IL-15 protein expression in fluid from the nasal mucosa and in bronchial biopsies was increased. In mice, RV induced type I IFN-dependent expressions of IL-15 and IL-15Rα, which in turn were required for NK- and CD8(+) T-cell responses. Treatment with IL-15-IL-15Rα complexes (IL-15c) boosted RV-induced expression of IL-15, IL-15Rα, IFN-γ, CXCL9, and CXCL10 followed by recruitment of activated, IFN-γ-expressing NK, CD8(+), and CD4(+) T cells. Treating infected IFNAR1(-/-) mice with IL-15c similarly increased IL-15, IL-15Rα, IFN-γ, and CXCL9 (but not CXCL10) expression also followed by NK-, CD8(+)-, and CD4(+)-T-cell recruitment and activation. We have demonstrated that type I IFN-induced IFN-γ and cellular immunity to RV was mediated by IL-15 and IL-15Rα. Importantly, we also show that IL-15 could be induced via a type I IFN-independent mechanism by IL-15 complex treatment, which in turn was sufficient to drive IFN-γ expression and lymphocyte responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Disease Models, Animal
  • Humans
  • Interferon Type I / metabolism*
  • Interleukin-15 / metabolism*
  • Killer Cells, Natural / immunology*
  • Mice
  • Picornaviridae Infections / immunology*
  • Rhinovirus / immunology*
  • Signal Transduction / immunology*
  • T-Lymphocytes / immunology*
  • Up-Regulation

Substances

  • Interferon Type I
  • Interleukin-15