title: Sepsis induces incomplete M2 phenotype polarization in peritoneal exudate cells in mice.
abstract: BACKGROUND
  Macrophages can differentiate into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes upon exposure to a pathogen or a cytokine microenvironment. However, M1/M2 macrophage polarization in polymicrobial sepsis has not been fully characterized.
  
  
  METHODS
  The polarity of peritoneal exudate (PE) cells from mice that had undergone cecal ligation and puncture (CLP) and the response of those cells to lipopolysaccharide (LPS) in terms of cytokine and chemokine expression were examined.
  
  
  RESULTS
  PE cells from CLP mice demonstrated a shift toward the M2 phenotype in terms of marker enzyme expression. In addition, the CLP-derived PE cells showed apparent unresponsiveness to LPS stimulation with regard to expression of pro-inflammatory cytokines such as TNF-α, while the expression of anti-inflammatory cytokines such as IL-10 was induced. Nevertheless, the CLP-PE cells failed to express M2 chemokines including chemokine (C-C motif) ligand 17 (CCL17), CCL22, and CCL24, all of which are important for T cell recruitment.
  
  
  CONCLUSIONS
  The results suggested that a shift of naïve monocytes/macrophages to the M2 phenotype, along with the lack of M2 chemokine expression in septic monocytes/macrophages, might be responsible for immunosuppression after sepsis.
authors.affiliation: Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Watanabe
authors.affiliation: Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Suzuki
authors.affiliation: Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Sadaki
authors.initials: S
authors.lastname: Inokuchi
authors.affiliation: Department of Emergency and Critical Care Medicine, Tokai University School of Medicine, Shimokasuya 143, Isehara, Kanagawa 259-1193 Japan.
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Inoue
keywords: Immunosuppression; Macrophage; Secondary infection; Sepsis