Effect of W07-toxin on gut physiological response in mice.

A number of unknown secretogenic factor(s) from Vibrio cholerae have been implicated to play a role in inducing cholera-like symptoms observed in patients. The present study has been carried out on the novel W07-toxin (pI 5.2) from V. cholerae W07, an epidemic cholera strain devoid of the ctx gene. The toxin showed maximum binding to GM(1) and interacted with a 20 kDa glycoprotein present on the cell membrane of mice enterocytes in a GM(1) specific manner. The analysis of biochemical parameters in enterocytes triggered with this toxin revealed a significant increase in intracellular calcium concentration and a massive secretion of Cl(-). However, no absorption of Na(+) was observed under the same condition. This toxin also elevated the level of cyclic adenosine 3',5'-monophosphate (cAMP) as well as protein kinase A (PKA). Thus, the novel toxin, although distinct from cholera-toxin, showed some functional homology to it and may be one of the key players inducing electrolyte imbalance within intestinal cells in the cholera-like symptoms associated with V. cholerae W07.