Surface blebbing and cytoskeletal changes induced in vitro by toxin B from Clostridium difficile: An immunochemical and ultrastructural study

W. Malorni, C. Fiorentini, S. Paradisi, M. Giuliano, P. Mastrantonio, G. Donelli

Research output: Contribution to journalArticlepeer-review

Abstract

Clostridium difficile toxin B is a powerful cytopathic agent without enterotoxic activity which is believed to be involved in the pathogenesis of pseudomembranous colitis. Up until today, the mechanisms of toxin B cytotoxicity have not been elucidated. The results of in vitro studies performed on different cell lines by means of immunocytochemical and ultrastructural methods are reported here. Low doses (0.15 ng/ml) of toxin B cause cell rounding and arborization. Higher doses (up to 15 μg/ml) induce cell rounding and appearance of numerous surface protrusions with blister or bulb-like features. These "blebs" belong to the potocytotic type, the bleb matrix being devoid of cytoplasmic organelles and filled with ribosomes only. Furthermore, a peculiar role of cytoskeletal apparatus in this phenomenon has been detected. In fact, morphological rearrangement occurs in cytoskeletal elements, mainly represented by the presence, in the blebs, of tubulin and of the actin-binding proteins α-actinin, filamin, and calmodulin, while actin and intermediate filaments, keratin and vimentin, appear to be absent. Moreover, β2-microglobulin, considered as a surface protein marker, seems to undergo changes in its expression, being absent over the blebbing surface. The results of this study may support the view that C. difficile toxin B affects one or more subcellular components that regulate the structure and function of the actin cytoskeleton.

Original languageEnglish
Pages (from-to)340-356
Number of pages17
JournalExperimental and Molecular Pathology
Volume52
Issue number3
DOIs
Publication statusPublished - 1990

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Molecular Biology
  • Pathology and Forensic Medicine

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