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January 1987

Role of the Macrophage in the Translocation of Intestinal Bacteria

Author Affiliations

From the Departments of Surgery (Drs Wells, Maddaus, and Simmons), Microbiology (Dr Simmons), and Laboratory Medicine and Pathology (Dr Wells), University of Minnesota, Minneapolis.

Arch Surg. 1987;122(1):48-53. doi:10.1001/archsurg.1987.01400130054008

• To clarify the role of the macrophage in the translocation of intestinal bacteria, groups (n = 10) of Swiss Webster mice (immunocompetent) and C3H/HeJ mice (macrophage defective) were given bacitracin/streptomycin in their drinking water to eliminate the majority of the intestinal microflora. These mice were then "monoassociated" with a streptomycin-resistant strain of Escherichia coli. Forty-eight hours later, E coli was present in all animals at a concentration of 1011/g of cecum. In four separate experiments, E coli was recovered from 100% of the mesenteric lymph nodes (MLNs) of the immunocompetent Swiss Webster mice and from 10%, 40%, 30%, and 50% of the MLNs of macrophage-defective C3H/HeJ mice. Swiss Webster mice were then similarly monoassociated by antibiotic decontamination followed by administration of antibiotic-resistant, fluorescein-labeled E coli in their drinking water; cohort groups of mice were given fluorescein-labeled latex beads (1 μm in diameter) in their drinking water. Two, four, and 11 days later, the MLNs were removed and single cell suspensions were analyzed in the fluorescence-activated cell sorter. The fluorescein label was detected exclusively in the macrophage (esterase-positive) population. These results support the hypothesis that intestinal macrophages may play a key role in the transport of intestinal particles (including bacteria) into extra-intestinal sites.

(Arch Surg 1987;122:48-53)