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Updated: Oct 13, 2026
Cefoperazone-treated Mouse Model of Clinically-relevant Clostridium difficile Strain R20291
Published on: December 10, 2016
Absence of intestinal secretion on supernatants from macrophages stimulated with Clostridium difficile toxin B on
M F Rocha1, A M Soares, R A Ribeiro
1Department of Physiology and Pharmacology, School of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil.
Abstract:
Several studies have documented the involvement of both Clostridium difficile, toxins, A and B in the pathogenesis of antibiotic-associated diarrhea. Recently, we demonstrated that IL-1 beta is the intestinal secretory factor released by macrophages stimulated with toxin A. The aim of this study was to evaluate the importance of macrophages stimulated with toxin B on rabbit ileal ion transport. The changes in ion transport were analyzed by studying the short-circuit current of the rabbit ileal mucosa mounted in Ussing chambers. The supernatants of macrophages treated with toxin B (3.6 x 10(-7) M) had no effect on the ion transport (change in short-circuit current =28.0+/-9.2 vs. control=26.8+/-3.6 microA cm(-2)). Supernatants of macrophages stimulated with toxin A (3.2 x 10(-7) M), our positive control, induced a significant change in ileal ion transport (delta I(sc)=55.2+/-5.7 mA cm(-2)). It was also observed that, like toxin A, toxin B stimulated macrophages to produce TNF-alpha (555.0+/-37.9 pg/ml vs. control=182.0+/-39.8 pg/ml; p<0.05). Nevertheless, in contrast to toxin A, toxin B did not stimulate IL-1 beta synthesis (28.0+/-7.5 pg/ml vs. control=40. 0+/-14.4 pg/ml; p>0.05). We conclude that the supernatants of macrophages stimulated with toxin B are not able to stimulate ion transport and that both toxins stimulate the genesis of TNF-alpha, but only toxin A induces the synthesis of IL-1 beta, which, we have earlier reported, causes an electrogenic intestinal response in rabbit ileum.
Insights
Clostridium difficile toxin B does not affect intestinal ion transport, unlike toxin A. Both toxins induce TNF-alpha, but only toxin A stimulates IL-1 beta, crucial for intestinal response in antibiotic-associated diarrhea.
Area of Science:
- Gastroenterology
- Immunology
- Microbiology
Background:
- Clostridium difficile toxins A and B are implicated in antibiotic-associated diarrhea pathogenesis.
- Interleukin-1 beta (IL-1 beta) was previously identified as an intestinal secretory factor released by macrophages stimulated with toxin A.
Purpose of the Study:
- To investigate the role of macrophages stimulated with Clostridium difficile toxin B in rabbit ileal ion transport.
- To compare the effects of toxin A and toxin B on macrophage cytokine production and intestinal ion transport.
Main Methods:
- Rabbit ileal mucosa mounted in Ussing chambers was used to measure short-circuit current, indicating ion transport changes.
- Supernatants from macrophages treated with toxin A or toxin B were applied to the ileal mucosa.
- Macrophage cytokine production (TNF-alpha and IL-1 beta) was quantified using ELISA.
Main Results:
- Supernatants from macrophages stimulated with toxin B did not alter ileal ion transport.
- Supernatants from macrophages stimulated with toxin A significantly increased ileal ion transport.
- Both toxin A and toxin B stimulated macrophages to produce TNF-alpha.
- Only toxin A, not toxin B, stimulated IL-1 beta synthesis by macrophages.
Conclusions:
- Clostridium difficile toxin B-stimulated macrophages do not induce changes in intestinal ion transport.
- While both toxins stimulate TNF-alpha production, only toxin A triggers IL-1 beta synthesis, which is responsible for the electrogenic intestinal response.
