Stimulation of steroidogenesis in tissue culture by enterotoxigenic Escherichia coli and its neutralization by specific antiserum.

Y1 adrenal cells in monolayer tissue culture react to culture filtrates from enterotoxigenic strains of Escherichia coli, but not to those from nontoxigenic strains, by undergoing morphological changes similar to those inducible by cholera enterotoxin and increasing their production of steroids. Heating destroys the ability of crude preparations of the E. coli enterotoxin to effect these tissue culture changes. None of a number of culture filtrates of other enteric or enteropathogenic bacteria were capable of inducing either the morphological changes or steroidogenesis. The maximal degree of steroidogenesis achievable with E. coli enterotoxin was comparable to that of cholera enterotoxin and could not be further increased by combination of the two toxins. As with cholera enterotoxin, removal of the E. coli toxin from the tissue culture medium after an initial brief exposure of the cells to the toxin was accompanied by some decrease in maximal steroidogenesis and no changes in either the onset or the permanency of the morphological changes. Antiserum raised to one of the crude E. coli enterotoxins was capable of completely neutralizing the steroidogenic effects and preventing the morphological changes secondary to a variety of different enterotoxigenic strains of E. coli. At the concentrations tested, this antiserum was not effective in preventing these same tissue culture changes inducible by cholera enterotoxin. The results of these and other related experiments suggest that cholera and heat-labile E. coli enterotoxins have similar mechanisms of action which are dissimilar to those of the other enterotoxins thus far described and tested.