the antigenicity of the escherichia coli heat-labile enterotoxin was not protected against the adverse effect of gastric acidity when the toxin was given together with bicarbonate for peroral immunization to rats , but immunization with the heat-labile enterotoxin encapsulated in ph-dependent microspheres aroused the same strong degree of serum and mucosal antitoxin responses and of protection against challenge as was achieved by peroral immunization after ablation of gastric secretions by pretreatment with cimetidine .
C0040549
toxin
C0014372
enterotoxin