Open AccessKinetics of KB and HEp‐2 cell responses to an invasive, cytolethal distending toxin‐producing strain of Actinobacillus actinomycetemcomitans
Author(s) -
DiRienzo J. M.,
Song M.,
Wan L. S. Y.,
Ellen R. P.
Publication year - 2002
Publication title -
oral microbiology and immunology
Language(s) - English
Resource type - Journals
eISSN - 1399-302X
pISSN - 0902-0055
DOI - 10.1034/j.1399-302x.2002.170407.x
Subject(s) - cytolethal distending toxin , actinobacillus , microbiology and biotechnology , biology , toxin , pathogen , strain (injury) , cell culture , cytotoxicity , gentamicin protection assay , bacteria , pasteurellaceae , cell , in vitro , microbial toxins , biochemistry , western blot , antibiotics , genetics , gene , anatomy , haemophilus influenzae
The periodontal pathogen Actinobacillus actinomycetemcomitans produces cytolethal distending toxin (CDT), a complex multicomponent toxin that arrests the growth of many types of eukaryotic cell. The kinetics of the effects of CDT‐containing extracts, from an invasive strain of this bacterium, were examined on epithelial‐like cells routinely used in invasion studies. Both KB and HEp‐2 cells were exquisitely sensitive to the effects of the CDT with TD 50 of 30 and 300 pg of total bacterial protein, respectively. Initial cell morphology changes were relatively rapid, occurring within the first 13 h of exposure. CDT‐treated KB cells increased in size to 4–5 times the size of untreated controls. Cytotoxicity was irreversible when attached cells were incubated, for a minimum of 120 min, with nanogram quantities of CDT‐containing extract. As cultures aged, the cells became more resistant to the effects of the CDT‐containing extracts. These findings have important implications for understanding the ability of A. actinomycetemcomitans to invade and multiply in epithelial cells.