Real-time cell analysis for monitoring cholera toxin-induced human intestinal epithelial cell response

The pathogenic mechanism of Vibrio cholerae manifests as diarrhea and causes life-threatening dehydration. Here, we observe the human intestinal epithelial cells (HIEC) response to Cholera toxin (CT) by a real-time cell analysis (RTCA) platform, and disclose the difference from CT-induced cytotoxicity and others in HIEC. An HIEC cell of 1.0 × 10(5) cells/mL was characterized as the suitable concentration for each well. For experimentation, the assay requires an inoculation of CT dissolved in Dulbecco's phosphate-buffered saline with 0.1 % gelatin for a period of 18-25 h. The dimensionless impedance cell index curve presented characteristic dose- and time-dependent drop responses at the first stage, and the CT-induced cytotoxicity was the most remarkable following exposure for 18-25 h (P = 0.0002). Following the obvious cytotoxic reaction, the CI curve gradually increased over time until the original CI value, indicating that self-recovery occurred. The CT-induced CI curve for HIEC was different from that induced by other toxins, including diphtheria and Clostridium difficile toxin. Collectively, these results suggest that the CT-induced cytotoxicity in HIEC was absolutely different from that induced by C. difficile and other toxins because of the different pathogeneses that were correlated with the specific CI curve generated by the RTCA system. In summary, our data show that the assay described here is a convenient and rapid high-throughput tool for real-time monitoring of host cellular responses to CT on the basis of the characteristic CI curve.