Cross-neutralization of heat-stable enterotoxin activity of enterotoxigenic Escherichia coli and of Yersinia enterocolitica

Enterotoxigenic Escherichia coli produces two kinds of enterotoxin, heat-labile (LT) and heat-stable (ST). ST-like enterotoxin is reported to be produced by other bacteria, such as Yersinia enterocolitica [1 ], Klebsiella pneumoniae [2] and Enterobacter cloacae [3]. Previously, we suggested an immunological relatedness between E. coli ST and Y. enterocolitica ST by demonstrating the neutralization of crude E. coli ST by anti-Y, enterocolitica ST. As a confirmation, we demonstrate in this paper the cross-neutralization of purified ST preparations of E. coli and Y. enterocolitica. a 5-liter minijar fermentor equipped with a pHcontrol unit, at 25°C for 48 h with constant aeration (3 liters/rain) with stirring (400 rev./min).