Rational design of adjuvants for subunit vaccines: The format of cationic adjuvants affects the induction of antigen-specific antibody responses

A range of cationic delivery systems have been investigated as vaccine adjuvants, though few direct comparisons exist. To investigate the impact platform, we prepared four (emulsions, liposomes, polymeric nanoparticles and solid lipid nanoparticles) all containing equal concentrations dimethyldioctadecylammonium bromide in combination with Neisseria adhesin variant 3 subunit antigen. The formulations were physicochemically characterized their ability to associate cells promote antigen processing (based on degradation DQ-OVA, a substrate for proteases which upon hydrolysis is fluorescent) was compared vitro efficacy (antigen-specific antibody responses IFN-? production) biodistribution (antigen adjuvant) evaluated vivo . Due nature, gave high loading (> 85%) emulsions being <200 nm, whilst larger (~350 nm). In vitro, particulate tended cell uptake processing, less effective. Similarly, induced depot (of both system antigen) at injection site, did not. However, out tested highest responses. These results demonstrate that while lipids can strong adjuvant activity, formulation platform influences immunogenicity.