The effect of oral immunisation with heat stable Escherichia coli antigens on the sensitivity of pigs to enterotoxins.

It was found that oral immunisation of pigs with heat stable Escherichia coli antigens resulted in a decrease in the sensitivity of the porcine intestine to both the heat stable (ST) and the heat labile (LT) and the heat labile (LT) form of the enterotoxin produced by enterotoxigenic strains. Antitoxic factors capable of neutralising LT, but not ST, could be passively transferred in the intestinal secretions of the immunised animals.