Specific receptor for Escherichia coli heat-stable enterotoxin (ST_a) may determine susceptibility of piglets to diarrheal disease

We have demonstrated the existence of a receptor that is specific for the Escherichia coli heat-stable enterotoxin (ST_a) on piglet's small intestine. The binding of ST_a to this receptor seemed specific, saturable and reversible. The receptor was demonstrated on brush border cells and membranes prepared from all of the piglets (n = 24) that developed clinical diarrhea when challenged with purified ST_a enterotoxin at the dose of 100 μg/kg body weight. The receptor was not demonstrated on intestinal brush border cells and membrane prepared from piglets (n = 3) that were refractory to the experimental induction of diarrhea. The data suggest that binding of the ST_a to a specific receptor on the small intestine of piglets is a prerequisite to the diarrheal response triggered by this toxin.