Pivotal Advance: Invariant NKT cells reduce accumulation of inflammatory monocytes in the lungs and decrease immune-pathology during severe influenza A virus infection

J Leukoc Biol. 2012 Mar;91(3):357-68. doi: 10.1189/jlb.0411184. Epub 2011 Oct 14.

Abstract

Little is known of how a strong immune response in the lungs is regulated to minimize tissue injury during severe influenza A virus (IAV) infection. Here, using a model of lethal, high-pathogenicity IAV infection, we first show that Ly6C(hi)Ly6G(-) inflammatory monocytes, and not neutrophils, are the main infiltrate in lungs of WT mice. Mice devoid of iNKT cells (Jα18(-/-) mice) have increased levels of inflammatory monocytes, which correlated with increased lung injury and mortality (but not viral load). Activation of iNKT cells correlated with reduction of MCP-1 levels and improved outcome. iNKT cells were able to selectively lyse infected, MCP-1-producing monocytes in vitro, in a CD1d-dependent process. Our study provides a detailed profile and kinetics of innate immune cells in the lungs during severe IAV infection, highlighting inflammatory monocytes as the major infiltrate and identifying a role for iNKT cells in control of these cells and lung immune-pathology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Blocking / administration & dosage
  • Antibodies, Blocking / immunology
  • Antigens, CD1d / metabolism
  • Antigens, Ly / metabolism
  • Chemokine CCL2 / immunology
  • Chemokine CCL2 / metabolism
  • Humans
  • Immunophenotyping
  • Inflammation / immunology*
  • Inflammation / metabolism
  • Inflammation / pathology
  • Influenza A virus / immunology*
  • Lung / immunology*
  • Lung / metabolism
  • Lung / pathology
  • Lymphocyte Activation / immunology
  • Macrophages / immunology
  • Macrophages / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Monocytes / immunology*
  • Monocytes / pathology
  • Monocytes / virology
  • Natural Killer T-Cells / immunology*
  • Orthomyxoviridae Infections / immunology*
  • Orthomyxoviridae Infections / mortality
  • Orthomyxoviridae Infections / pathology*
  • Respiratory Mucosa / immunology
  • Respiratory Mucosa / metabolism
  • Respiratory Mucosa / virology

Substances

  • Antibodies, Blocking
  • Antigens, CD1d
  • Antigens, Ly
  • Chemokine CCL2