Bacillus Calmette-Guerin Infection in NADPH Oxidase Deficiency: Defective Mycobacterial Sequestration and Granuloma Formation

PLoS Pathogens

Karl-Heinz Krause¹  Michela G. Schäppi¹  Christine Deffert¹  Julien Cachat¹  Ruth Bisig¹  Xiaojuan Ma Mulone¹  Dominique Vesin¹  Jean-Claude Pache²  Rikard Holmdahl³  Maria L. Olleros³  Irene Garcia⁴  Tiina Kelkka⁴ 

[1] Department of Pathology and Immunology, Medical Faculty and University of Geneva, Geneva, Switzerland;Division of Clinical Pathology, Department of Pathology and Immunology, Medical Faculty and University of Geneva, Geneva, Switzerland;Section of Medical Inflammation Research, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Solna, Sweden;Section of Medical Inflammation Research, Medicity Research Laboratory, University of Turku, Finland

关键词: Mouse models;    Granulomas;    Macrophages;    Phagocytes;    Neutrophils;    Cytokines;    Animal models of infection;    Mycobacterium bovis;   

DOI  :  10.1371/journal.ppat.1004325

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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.

【 授权许可】

CC BY