Bacillus calmette-guerin infection in NADPH oxidase deficiency: defective mycobacterial sequestration and granuloma formation

PLoS Pathog. 2014 Sep 4;10(9):e1004325. doi: 10.1371/journal.ppat.1004325. eCollection 2014 Sep.

Abstract

Patients with chronic granulomatous disease (CGD) lack generation of reactive oxygen species (ROS) through the phagocyte NADPH oxidase NOX2. CGD is an immune deficiency that leads to frequent infections with certain pathogens; this is well documented for S. aureus and A. fumigatus, but less clear for mycobacteria. We therefore performed an extensive literature search which yielded 297 cases of CGD patients with mycobacterial infections; M. bovis BCG was most commonly described (74%). The relationship between NOX2 deficiency and BCG infection however has never been studied in a mouse model. We therefore investigated BCG infection in three different mouse models of CGD: Ncf1 mutants in two different genetic backgrounds and Cybb knock-out mice. In addition, we investigated a macrophage-specific rescue (transgenic expression of Ncf1 under the control of the CD68 promoter). Wild-type mice did not develop severe disease upon BCG injection. In contrast, all three types of CGD mice were highly susceptible to BCG, as witnessed by a severe weight loss, development of hemorrhagic pneumonia, and a high mortality (∼ 50%). Rescue of NOX2 activity in macrophages restored BCG resistance, similar as seen in wild-type mice. Granulomas from mycobacteria-infected wild-type mice generated ROS, while granulomas from CGD mice did not. Bacterial load in CGD mice was only moderately increased, suggesting that it was not crucial for the observed phenotype. CGD mice responded with massively enhanced cytokine release (TNF-α, IFN-γ, IL-17 and IL-12) early after BCG infection, which might account for severity of the disease. Finally, in wild-type mice, macrophages formed clusters and restricted mycobacteria to granulomas, while macrophages and mycobacteria were diffusely distributed in lung tissue from CGD mice. Our results demonstrate that lack of the NADPH oxidase leads to a markedly increased severity of BCG infection through mechanisms including increased cytokine production and impaired granuloma formation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cytokines / metabolism
  • Female
  • Granuloma / immunology
  • Granuloma / pathology*
  • Humans
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mycobacterium Infections / immunology
  • Mycobacterium Infections / microbiology*
  • Mycobacterium Infections / pathology*
  • Mycobacterium bovis / pathogenicity*
  • NADPH Oxidases / physiology*
  • Nitric Oxide Synthase Type II / metabolism
  • Reactive Oxygen Species / metabolism
  • Tyrosine / analogs & derivatives
  • Tyrosine / metabolism

Substances

  • Cytokines
  • Reactive Oxygen Species
  • 3-nitrotyrosine
  • Tyrosine
  • Nitric Oxide Synthase Type II
  • Nos2 protein, mouse
  • NADPH Oxidases

Grants and funding

This work was supported by the FNS (310030B-141182 to KHK), SER (Science and Technology Cooperation Program Switzerland-Russia to IG), FRNS (310030-146833 to IG) grants, Ligue Pulmonaire Genevoise (to IG), Fondation Ernst et Lucie Schmidheiny (to MLO), the Swedish Strategic Science Foundation, the EU grants, the Innovative Medicine Initiative program BeTheCure (to RH), and Neurinox (HEALTH-F2-2011-278611). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.