Gr1(+) inflammatory monocytes are required for mucosal resistance to the pathogen Toxoplasma gondii

Immunity. 2008 Aug 15;29(2):306-17. doi: 10.1016/j.immuni.2008.05.019.

Abstract

The enteric pathogen Toxoplasma gondii is controlled by a vigorous innate T helper 1 (Th1) cell response in the murine model. We demonstrated that after oral infection, the parasite rapidly recruited inflammatory monocytes [Gr1(+) (Ly6C(+), Ly6G(-)) F4/80(+)CD11b(+)CD11c(-)], which established a vital defensive perimeter within the villi of the ileum in the small intestine. Mice deficient of the chemokine receptor CCR2 or the ligand CCL2 failed to recruit Gr1(+) inflammatory monocytes, whereas dendritic cells and resident tissue macrophages remained unaltered. The selective lack of Gr1(+) inflammatory monocytes resulted in an inability of mice to control replication of the parasite, high influx of neutrophils, extensive intestinal necrosis, and rapid death. Adoptive transfer of sorted Gr1(+) inflammatory monocytes demonstrated their ability to home to the ileum in infected animals and protect Ccr2(-/-) mice, which were otherwise highly susceptible to oral toxoplasmosis. Collectively, these findings illustrate the critical importance of inflammatory monocytes as a first line of defense in controlling intestinal pathogens.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Chemokine CCL2 / deficiency
  • Chemokine CCL2 / immunology
  • Chemokine CCL2 / metabolism*
  • Cytokines / blood
  • Immunity, Mucosal
  • Intestinal Mucosa / metabolism
  • Intestines / immunology
  • Intestines / parasitology
  • Mice
  • Mice, Knockout
  • Monocytes / cytology
  • Monocytes / immunology*
  • Monocytes / metabolism
  • Monocytes / parasitology
  • Receptors, CCR2 / deficiency
  • Receptors, CCR2 / immunology
  • Receptors, CCR2 / metabolism*
  • Th1 Cells / immunology*
  • Th1 Cells / metabolism
  • Th1 Cells / parasitology
  • Toxoplasma / immunology*
  • Toxoplasmosis, Animal / immunology*
  • Toxoplasmosis, Animal / parasitology
  • Toxoplasmosis, Animal / pathology

Substances

  • Ccr2 protein, mouse
  • Chemokine CCL2
  • Cytokines
  • Receptors, CCR2