Clostridium difficile toxin B induces apoptosis in intestinal cultured cells

Carla Fiorentini, Alessia Fabbri, Loredana Falzano, Andrea Fattorossi, Paola Matarrese, Roberto Rivabene, Gianfranco Donelli

Research output: Contribution to journalArticlepeer-review


Toxigenic strains of the anaerobic bacterium Clostridium difficile produce at least two large, single-chain protein exotoxins involved in the pathogenesis of antibiotic-associated diarrhea and colitis. Toxin A (CdA) is a cytotoxic enterotoxin, while toxin B (CdB) is a more potent cytotoxin lacking enterotoxic activity. This study dealt with CdB, providing the first evidence that intestinal cells exposed to this toxin exhibit typical features of apoptosis in that a significant proportion of the treated cells displayed nuclear fragmentation and chromatin condensation. In keeping with ultrastructural data, CdB-treated cells showed the typical flow cytometric hallmark of apoptosis consisting of a distinct sub-G1 peak. The CdB-induced apoptotic response was dose and time dependent and not simply due to the actin-disrupting effect of the toxin or to the subsequent impairment of cell anchorage. Rather, the inhibition of proteins belonging to the Rho family due to CdB seems to play a role in the induction of apoptosis in intestinal cells. The origin of cells and the growth rate may also be cofactors relevant to such a response.

Original languageEnglish
Pages (from-to)2660-2665
Number of pages6
JournalInfection and Immunity
Issue number6
Publication statusPublished - Jun 1998

ASJC Scopus subject areas

  • Immunology


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