Enhanced Immune Response Against Pertussis Toxoid by IgA-Loaded Chitosan–Dextran Sulfate Nanoparticles

The objective of the present study was to evaluate immunological activities of chitosan–dextran sulfate (CS–DS) nanoparticle formulation of pertussis toxoid (PTXd) and its combination with a potential immunological adjuvant, immunoglobulin A (IgA). CS–DS nanoparticles were prepared using a complex coacervation (polyelectrolyte complexation) technique. CS–DS nanoparticle formulations with size and zeta potential in a range of 300–350nm and +40–+55mV, respectively, were obtained. An entrapment efficiency of more than 90% was obtained for pertussis toxin and IgA in CS–DS nanoparticles. All loaded nanoparticle formulations showed less than 20% of release within 24h in in vitro release studies. The immunological evaluation of developed formulations in female Balb/c mice groups showed that the CS–DS nanoparticles formulations induced significantly higher serum IgG and IgG1 titers (p < 0.05) as compared with conventional alum-adjuvanted PTXd formulation administered by subcutaneous route. This study indicated the potential of CS–DS nanoparticles to be a simple and effective particulate delivery system with in-built immunological adjuvant property for acellular protein antigens. The study also revealed the potential important role of IgA-loaded CS–DS nanoparticles as a novel immunological adjuvant for vaccine delivery. © 2011 Wiley Periodicals, Inc. and the American Pharmacists Association.