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Infect. Immun., 07 1997, 2740-2746, Vol 65, No. 7
MF Rocha, ME Maia, LR Bezerra, DM Lyerly, RL Guerrant, RA Ribeiro and AA Lima
Clostridium difficile produces a potent enterotoxin and cytotoxin, toxins A
and B, respectively, which appear to be responsible for pseudomenbranous
colitis and antibiotic-associated diarrhea. In the present study we
explored the neutrophil migration evoked by toxin A in the peritoneal
cavities and subcutaneous air pouches of rats and examined the role of
macrophages and their inflammatory mediators in this process. Toxin A
causes a significant dose-dependent neutrophil influx into the peritoneal
cavity, with a maximal response at 0.1 microg/ml and at 4 h. The depletion
of macrophages by peritoneal washing prevents the toxin A-induced
neutrophil migration into the peritoneal cavity. In contrast, an increase
in macrophages induced by peritoneal injection of thioglycolate amplifies
this toxin effect on neutrophil migration. Furthermore, the injection of
supernatants from toxin A-stimulated macrophages into the rat peritoneal
cavity causes significant neutrophil migration. Pretreatment of rats with
BWA4C, nordihydroguaiaretic acid, mepacrine, or dexamethasone inhibits the
neutrophil migration evoked by toxin A in the peritoneal cavities. However,
pretreatment with the cyclooxygenase inhibitor indomethacin or the
platelet-activating factor antagonist BN52021 fails to alter toxin
A-induced neutrophil migration. Toxin A was also injected into air pouches
of normal rats or rats pretreated with anti-interleukin-1beta
(anti-IL-1beta) or anti-tumor necrosis factor alpha (anti-TNF-alpha)
antibodies. Anti-TNF-alpha or anti-IL-1beta antibodies significantly reduce
the neutrophil migration induced by toxin A. These data suggest that
neutrophil migration evoked by toxin A is in part dependent on
macrophage-derived cytokines, such as TNF-alpha and IL-1beta, and
leukotrienes. These mediators may help to explain the intense inflammatory
colitis caused by C. dificile toxin A in an experimental animal model of
this disease.
Copyright © 1997, American Society for Microbiology
Clostridium difficile toxin A induces the release of neutrophil chemotactic factors from rat peritoneal macrophages: role of interleukin-1beta, tumor necrosis factor alpha, and leukotrienes
Department of Physiology and Pharmacology, Health Sciences Center, Federal University of Ceara, Fortaleza-CE, Brazil.
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