Orally administered microencapsulated Bordetella pertussis fimbriae protect mice from B-pertussis respiratory infection

Fimbriae from Bordetella pertussis have been encapsulated in poly(lactide-co-glycolide) microparticles of a size appropriate for uptake by the immune inductive tissues of the gastrointestinal tract. Mice were immunized by oral gavage,vith a single dose of 10 mu g of microencapsulated fimbriae. The resulting immune responses were compared with those resulting from intraperitoneal injection of mice with equivalent amounts of fimbriae adsorbed onto alhydrogel. The examination of serum and mucosal secretions, collected over a 6-week period, for specific antifimbrial antibodies clearly demonstrated that only orally immunized animals mounted measurable immune responses in external secretions. Six weeks after immunization, all immunized animals were protected against intranasal challenge with live B. pertussis.