Immunisation of volunteers with a synthetic peptide vaccine for enterotoxigenic Escherichia coli.

A completely synthetically produced peptide vaccine, consisting of the 18-aminoacid Escherichia coli heat-stable toxin and the 26-aminoacid epitope of the heat-labile toxin B subunit, was given orally to thirteen volunteers. It raised antitoxin titres to both toxin components four-fold in serum samples and seven-fold in jejunal aspirates over preimmunisation control titres. Jejunal aspirates taken after immunisation from vaccinees, but not controls, neutralised the secretory activity of both toxins in appropriate biological assays. These findings show that synthetically produced vaccines are immunogenic in human beings. The peptide used is a promising vaccine for diarrhoeal disease caused by enterotoxigenic strains of E coli.