Expression of α- and ε-toxin genes in Clostridium perfringens type D vaccine strain in contact with the Caco-2 cell line

Background: Clostridium perfringens commonly resides in the gastrointestinal tract and can survive in different environmental conditions. This pathogen produces several protein toxins including the potent εtoxin which is classified as a category B toxin by the Centers for Disease Control and Prevention (CDC). In several studies, the induction of C. perfringens type C or D to produce toxins much more rapidly by close contact of bacteria with Caco2 cells has been reported. Aims: The effect of close contact of enterocytelike Caco2 cells with C. perfringens type D (vaccine strain) on the production time of ε and αtoxins was studied. Methods: During C. perfringens type D contact with Caco2 cells for 5 h, ε and αtoxins expressions (at 0, 2, and 5 h) were evaluated by a quantitative realtime PCR assay. Noncontacted bacteria with cells were included as the negative control in this research. Results: Bacterial contact with the Caco2 cells induces a significant effect on the mean expression of the εtoxin gene (etx) (P lt;0.05). Two h after contact, the highest level of gene expression was detected in the experimental group. Bacterial harvesting time, cell treatment, and their interactions did not affect significantly the mean expression of the αtoxin gene (cpa) (P gt;0.05). Conclusion: According to the findings of the present study, 2 h of bacterial contact with Caco2 cells could stimulate etx gene expression in the C. perfringens type D vaccine strain.