PROTECTION OF MICE FROM BORDETELLA-PERTUSSIS RESPIRATORY-INFECTION USING MICROENCAPSULATED PERTUSSIS FIMBRIAE

Conditions have been established which allow the efficient entrapment of Bordetella pertussis fimbriae in poly(lactide-co-glycolide) microsp heres. Fimbriae released from the matrix were found to have retained s ome degree of conformational structure, as determined by assessing the capacity of fimbrial protein to bind to antibodies mapping to either conformational or denatured structures on the fimbriae. Following a si ngle intraperitoneal injection, equivalent amounts of fimbriae, either encapsulated in microspheres with a mean diameter of 24 mu m and an e stimated in vitro protein release rate of approximately 42 days, or co nventionally adjuvanted with alhydrogel, elicited vigorous immune resp onses in mice. The encapsulated fimbriae appear to elicit marginally l ower serum antibody levels than those induced by equivalent amounts of alhydrogel adjuvanted fimbriae. Mice immunised with both preparations were, however, protected against intranasal infection with live B. pe rtussis as evidenced by the significant reduction in levels of bacteri al colonisation observed in the lungs and tracheas of immunised animal s when compared to the immunologically naive controls.