Monocyte emigration from bone marrow during bacterial infection requires signals mediated by chemokine receptor CCR2

Nat Immunol. 2006 Mar;7(3):311-7. doi: 10.1038/ni1309. Epub 2006 Feb 5.


Monocytes recruited to tissues mediate defense against microbes or contribute to inflammatory diseases. Regulation of the number of circulating monocytes thus has implications for disease pathogenesis. However, the mechanisms controlling monocyte emigration from the bone marrow niche where they are generated remain undefined. We demonstrate here that the chemokine receptor CCR2 was required for emigration of Ly6C(hi) monocytes from bone marrow. Ccr2(-/-) mice had fewer circulating Ly6C(hi) monocytes and, after infection with Listeria monocytogenes, accumulated activated monocytes in bone marrow. In blood, Ccr2(-/-) monocytes could traffic to sites of infection, demonstrating that CCR2 is not required for migration from the circulation into tissues. Thus, CCR2-mediated signals in bone marrow determine the frequency of Ly6C(hi) monocytes in the circulation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Antigens, Ly / immunology
  • Antigens, Ly / metabolism
  • Bacterial Infections / immunology*
  • Bone Marrow Cells / cytology
  • Bone Marrow Cells / immunology
  • Cell Differentiation
  • Chemotaxis, Leukocyte / immunology*
  • Flow Cytometry
  • Mice
  • Monocytes / cytology
  • Monocytes / immunology*
  • Receptors, CCR2
  • Receptors, Chemokine / immunology*


  • Antigens, Ly
  • Ccr2 protein, mouse
  • Ly-6C antigen, mouse
  • Receptors, CCR2
  • Receptors, Chemokine