Alternative Activation Deprives Macrophages of a Coordinated Defense Program to Mycobacterium Tuberculosis

Eur J Immunol. 2006 Mar;36(3):631-47. doi: 10.1002/eji.200535496.

Abstract

A potent Th1 immune response is critical to the control of tuberculosis. The impact of an additive Th2 response on the course of disease has so far been insufficiently characterized, despite increased morbidity after co-infection with Mycobacterium tuberculosis and Th2-eliciting helminths and possible involvement of Th2 polarization in reactivation of latent tuberculosis. Here, we describe the gene expression profile of murine bone marrow-derived macrophages alternatively activated by IL-4 in response to infection with M. tuberculosis. Comparison of transcriptional profiles of infected IL-4- and IFN-gamma-activated macrophages revealed delayed and partially diminished responses to intracellular bacteria in alternatively activated macrophages, characterized by reduced exposure to nitrosative stress and increased iron availability, respectively. Alternative activation of host macrophages correlated with elevated expression of the M. tuberculosis iron storage protein bacterioferritin as well as reduced expression of the mycobactin synthesis genes mbtI and mbtJ. The extracellular matrix-remodeling enzyme matrix metalloproteinase (MMP)-12 was induced in alternatively activated macrophages in vitro, and MMP-12-expressing macrophages were abundant at late, but not early, stages of tuberculosis in murine lungs. Our findings emphasize that alternative activation deprives macrophages of control mechanisms that limit mycobacterial growth in vivo, thus supporting intracellular persistence of M. tuberculosis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Bacterial Proteins / immunology
  • Bone Marrow Cells / immunology*
  • Bone Marrow Cells / microbiology
  • Bone Marrow Cells / pathology
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / immunology*
  • Gene Expression Regulation, Bacterial / drug effects
  • Gene Expression Regulation, Bacterial / genetics
  • Gene Expression Regulation, Bacterial / immunology
  • Helminthiasis / immunology
  • Helminthiasis / pathology
  • Interferon-gamma / pharmacology
  • Interleukin-4 / pharmacology
  • Iron / immunology
  • Lung / immunology
  • Lung / microbiology
  • Lung / pathology
  • Macrophage Activation / drug effects
  • Macrophage Activation / immunology*
  • Macrophages / immunology*
  • Macrophages / microbiology
  • Macrophages / pathology
  • Matrix Metalloproteinase 12
  • Metalloendopeptidases / immunology
  • Mice
  • Mycobacterium tuberculosis / genetics
  • Mycobacterium tuberculosis / immunology*
  • Oxazoles / immunology
  • Th1 Cells / immunology
  • Th2 Cells / immunology
  • Tuberculosis, Pulmonary / genetics
  • Tuberculosis, Pulmonary / immunology*
  • Tuberculosis, Pulmonary / pathology

Substances

  • Antineoplastic Agents
  • Bacterial Proteins
  • Oxazoles
  • mycobactins
  • Interleukin-4
  • Interferon-gamma
  • Iron
  • Metalloendopeptidases
  • Matrix Metalloproteinase 12