IFN-γ primes bone marrow neutrophils to acquire regulatory functions in severe viral respiratory infections

Sci Adv. 2024 Oct 11;10(41):eadn3257. doi: 10.1126/sciadv.adn3257. Epub 2024 Oct 11.

Abstract

Neutrophil subsets endowed with regulatory/suppressive properties are widely regarded as deleterious immune cells that can jeopardize antitumoral response and/or antimicrobial resistance. Here, we describe a sizeable fraction of neutrophils characterized by the expression of programmed death-ligand 1 (PD-L1) in biological fluids of humans and mice with severe viral respiratory infections (VRI). Biological and transcriptomic approaches indicated that VRI-driven PD-L1+ neutrophils are endowed with potent regulatory functions and reduced classical antimicrobial properties, as compared to their PD-L1- counterpart. VRI-induced regulatory PD-L1+ neutrophils were generated remotely in the bone marrow in an IFN-γ-dependent manner and were quickly mobilized into the inflamed lungs where they fulfilled their maturation. Neutrophil depletion and PD-L1 blockade during experimental VRI resulted in higher mortality, increased local inflammation, and reduced expression of resolving factors. These findings suggest that PD-L1+ neutrophils are important players in disease tolerance by mitigating local inflammation during severe VRI and that they may constitute relevant targets for future immune interventions.

MeSH terms

  • Animals
  • B7-H1 Antigen* / genetics
  • B7-H1 Antigen* / metabolism
  • Bone Marrow / immunology
  • Bone Marrow / metabolism
  • Bone Marrow Cells / immunology
  • Bone Marrow Cells / metabolism
  • Female
  • Humans
  • Interferon-gamma* / metabolism
  • Lung / immunology
  • Lung / metabolism
  • Lung / pathology
  • Lung / virology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neutrophils* / immunology
  • Neutrophils* / metabolism
  • Respiratory Tract Infections* / immunology

Substances

  • Interferon-gamma
  • B7-H1 Antigen