The evidence of bacterial translocation are: (i) nosocomial infections have been correlated with indigenous gut bacteria (e.g. Escherichia coli) isolated in blood cultures and (ii) enteric microorganisms have been identified in the blood of cirrhotic patients with spontaneous bacterial
peritonitis 3. Antibiotics are effective in diminishing the colonization and multiplication of bacteria which are translocated from the intestine. However, Erlotinib nmr due to defects of the host’s antibacterial innate immunities, the very small amounts of bacteria that escape from these treatments are sufficient to spread systemically in thermally injured patients. Excessive antibiotic usage BAY 57-1293 mw (amounts and duration) leads to the generation of untreatable strains of bacteria. A new paradigm is needed to treat burn patients with bacterial translocation-related infectious complications. Therefore, we attempted to immunologically control infectious complications caused by bacterial translocation through the recovery of damaged host antibacterial defenses in thermally injured patients. The important roles of macrophages (Mϕs) in antibacterial innate immunity have been described in many papers 4–10. M1Mϕs (IL-12+ IL-23+ IL-10− Mϕs) generated from resident Mϕs by the stimulation with a microbial antigen or cytokines are potent effector cells that kill invaded microorganisms
11–13. In contrast, M2Mϕs (IL-12− IL-23− IL-10+ Mϕs) 14, 15 are shown to be inhibitory on Mϕ conversion from resident Mϕs to M1Mϕs 16. CCL17 and IL-10 released from M2Mϕs are characterized as effector molecules for inhibiting Mϕ conversion from resident Mϕs to M1Mϕs 16. Therefore, M1Mϕs are not generated in hosts
where M2Mϕs predominate 7, 17. CCL2 is a chemokine that attracts and activates mononuclear cells. The necessity of this chemokine for Th2-cell generation has been well demonstrated 18. Thus, CCL2-knockout mice resisted Leishmania major infection 18, while CCL2-overexpressing transgenic mice were susceptible to infections with Listeria monocytogenes or Mycobacterium Ribonucleotide reductase tuberculosis 19. We previously demonstrated that herpes encephalomyelitis 20 and cryptococcal encephalitis 21 are not severely developed in mice depleted of CCL2. Recently, the increased level of CCL2 has been demonstrated in sera of thermally injured patients 22 as well as severely burned mice 23. These mice have already been characterized as mice susceptible to sepsis stemming from Enterococcus faecalis translocation 24. In the subsequent study 25, utilizing CCL2 knockout mice, a role of CCL2 on resident Mϕ conversion into M1Mϕs or M2Mϕs was explored. In contrast to severely burned wild-type mice, M1Mϕs were induced and M2Mϕs were not induced in burned CCL2-knockout mice stimulated with the E. faecalis antigen.