Recruitment of Chlamydia pneumoniae-infected macrophages to the carotid artery wall in noninfected, nonatherosclerotic mice

Arterioscler Thromb Vasc Biol. 2003 May 1;23(5):789-94. doi: 10.1161/01.ATV.0000068645.60805.7C. Epub 2003 Mar 27.


Objective: Monocyte recruitment into the subendothelium is a crucial step in atherogenesis. Chlamydia pneumoniae resides in circulating monocytes and in the atherosclerotic vascular wall. However, the role of C pneumoniae for monocyte recruitment is unknown. The aim of this study was to examine the impact of C pneumoniae on monocyte adhesion and migration.

Methods and results: C pneumoniae-infected, fluorescence-labeled mouse macrophages (ANA-1) were injected intravenously into noninfected, healthy mice. In vivo videomicroscopy showed increased rolling and firm adhesion to the carotid artery compared with noninfected macrophages. In vitro, C pneumoniae infection (yielding 25% to 35% infected monocytes) increased adhesion of human monocytes or MonoMac6 cells to human umbilical vein endothelial cells and improved cell migration through endothelial-like ECV604 cells. Cell adhesion was inhibited by antibody blockade of very late antigen-4, lymphocyte function-associated antigen-1, macrophage antigen-1, or urokinase receptor, which were found upregulated or activated on C pneumoniae infection (flow cytometry). In contrast, C trachomatis did not induce monocyte adhesion at comparable infection rates (25% to 35%), indicating a unique activation pathway for C pneumoniae. Polymyxin B did not affect C pneumoniae-induced adhesion, excluding a relevant role of lipopolysaccharide in this process.

Conclusions: These data indicate that C pneumoniae can direct monocytes to predilection sites of nonatherosclerotic vessel walls in vivo by activation of the integrin adhesion receptor system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arteriosclerosis / etiology*
  • CD18 Antigens / physiology
  • Carotid Artery, Common / pathology*
  • Cell Adhesion
  • Cell Movement
  • Cells, Cultured
  • Chlamydia trachomatis / physiology
  • Chlamydophila pneumoniae / physiology*
  • Endothelial Cells / cytology
  • Endothelium, Vascular / cytology
  • Humans
  • Integrin alpha4beta1 / antagonists & inhibitors
  • Integrin alpha4beta1 / physiology
  • Lymphocyte Function-Associated Antigen-1 / physiology
  • Macrophage-1 Antigen / physiology
  • Macrophages / microbiology*
  • Macrophages / pathology
  • Macrophages / transplantation
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Microscopy, Video
  • Organ Specificity
  • Receptors, Cell Surface / antagonists & inhibitors
  • Receptors, Cell Surface / physiology
  • Receptors, Urokinase Plasminogen Activator


  • CD18 Antigens
  • Integrin alpha4beta1
  • Lymphocyte Function-Associated Antigen-1
  • Macrophage-1 Antigen
  • PLAUR protein, human
  • Plaur protein, mouse
  • Receptors, Cell Surface
  • Receptors, Urokinase Plasminogen Activator