Table of Contents
New Journal of Science
Volume 2014, Article ID 249056, 26 pages
Review Article

Cytolethal Distending Toxin: A Unique Variation on the AB Toxin Paradigm

Department of Microbiology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA

Received 25 June 2014; Accepted 12 August 2014; Published 25 September 2014

Academic Editor: Alejandra Bravo

Copyright © 2014 Joseph M. DiRienzo. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Some of the most potent toxins produced by plants and bacteria are members of a large family known as the AB toxins. AB toxins are generally characterized by a heterogenous complex consisting of two protein chains arranged in various monomeric or polymeric configurations. The newest class within this superfamily is the cytolethal distending toxin (Cdt). The Cdt is represented by a subfamily of toxins produced by a group of taxonomically distinct Gram negative bacteria. Members of this subfamily have a related AB-type chain or subunit configuration and properties distinctive to the AB paradigm. In this review, the unique structural and cytotoxic properties of the Cdt subfamily, target cell specificities, intoxication pathway, modes of action, and relationship to the AB toxin superfamily are compared and contrasted.