Enterotoxicity and cytotoxicity of Vibrio parahaemolyticus thermostable direct hemolysin in in vitro systems

Francesco Raimondi, Joseph P Y Kao, Carla Fiorentini, Alessia Fabbri, Gianfranco Donelli, Nicoletta Gasparini, Armido Rubino, Alessio Fasano

Research output: Contribution to journalArticlepeer-review


Vibrio parahaemolyticus is a marine bacterium known to be a common cause of seafood gastroenteritis worldwide. The thermostable direct hemolysin (TDH) has been proposed to be a major virulence factor of V. parahaemolyticus. TDH causes intestinal fluid secretion as well as cytotoxicity in a variety of cell types. In this study, we investigated the interplay between the hemolysin's enterotoxic and cytotoxic effects by using both human and rat cell monolayers. As revealed by microspectrofluorimetry, the toxin causes a dose-dependent increase in intracellular free calcium in both Caco-2 and IEC- 6 cells. This effect was reversible only when low toxin concentrations were tested. The TDH-activated ion influx pathway is not selective for calcium but admits ions such sodium and manganese as well. Furthermore, in the same range of concentration, the hemolysin triggers a calcium-dependent chloride secretion. At high concentrations, TDH induces a dose-dependent but calcium- independent cell death as assessed by functional, biochemical, and morphological assays.

Original languageEnglish
Pages (from-to)3180-3185
Number of pages6
JournalInfection and Immunity
Issue number6
Publication statusPublished - Jun 2000

ASJC Scopus subject areas

  • Immunology


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