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Keywords:

  • Bacterial translocation;
  • Burn;
  • CCL2;
  • Immunomodulation

Abstract

Severely burned mice are susceptible to sepsis stemming from Enterococcus faecalis translocation due to the impaired generation of M1 macrophages (M1Mϕs) in local translocation sites. In our previous studies, CCL2 has been characterized as a major effector molecule on the burn-associated generation of M2Mϕs, an inhibitor cell type for resident Mϕ conversion into M1Mϕs. In this study, we tried to protect burned mice orally infected with E. faecalis utilizing CCL2 antisense oligodeoxynucleotides (ODNs). We show that M2Mϕs in mesenteric lymph nodes (MLNs) were not demonstrated in burned mice treated with CCL2 antisense ODNs. M1Mϕs were not induced by heat-killed E. faecalis from resident Mϕs transwell-cultured with mesenteric lymph node macrophages (MLN-Mϕs) from burned mice, while M1Mϕs were induced by the same antigen from resident Mϕs transwell-cultured with Mϕs which were isolated from burned mice treated with CCL2 antisense ODNs. Bacterial growth in MLNs was shown in burned mice orally infected with a lethal dose of E. faecalis. However, after the same infection, sepsis did not develop in burned mice treated with CCL2 antisense ODNs. These results indicate that bacterial translocation and subsequent sepsis are controlled in burned mice orally infected with a lethal dose of E. faecalis by gene therapy utilizing CCL2 antisense ODNs.