Protection against Bordetella pertussis infection following parenteral or oral immunization with antigens entrapped in biodegradable particles: effect of formulation and route of immunization on induction of Th1 and Th2 cells

The immunogenicity and protective efficacy of systemically and orally deliv ered pertussis antigens entrapped in either microparticle poly-lactide-co-g lycolide (PLG) or nanoparticle PLG formulations were evaluated in a murine respiratory challenge model for infection with Bordetella pertussis. The re sults demonstrate that immunization with two parenteral doses of 1 mug or t hree oral doses of 100 mug of pertussis toroid (PTd) and filamentous haemag glutinin (FHA) encapsulated in PLG conferred a high level of protection aga inst B. pertussis challenge. Furthermore protection could be generated with a single parenteral immunization with a combined microparticle and nanopar ticle formulation. However. the route of immunization and the size of the p articles affected the type of T cell response induced. Parenteral immunizat ion with PTd and FHA entrapped in PLG microparticles elicits a potent type 1 T cell response and potent antibody response when given by the intraperit oneal (i.p.) or intramuscular (i.m.) route. In contrast, nanoparticle formu lations favoured the induction of Th2 cells. (C) 2001 Elsevier Science Ltd. All rights reserved.