Microencapsulated enterotoxigenic Escherichia coli and detached fimbriae for peroral vaccination of pigs

The feasibility of peroral immunisation with microencapsulated Escherichia coli and detached fimbriae to prevent enterotoxigenic E. coli infections in pigs was examined. For this E. coli and fimbriae were microencapsulated in to poly(lactide-co-glycolide) microspheres by spray-drying. Various microsp here formulations designed to deliver priming and booster doses were fed to new-born and weaned pigs. The pigs were challenged 19 days after the boost er dose by peroral administration of an infective dose of the homologous E. coli. Serum IgA antibody titres and excretion of challenge E. coli, as ind icators fur colonisation, were determined. The data showed that no signific ant serum antibodies were induced, and E. coli colonisation was not reduced by the peroral administration of the various antigen-loaded microspheres. These results are in contradiction to some of the previously published expe riments typically in rats or rabbits, where model antigens or unpractical i mmunisation procedures have frequently been used. (C) 2000 Elsevier Science Ltd. All rights reserved.