RECENT ADVANCES IN VACCINE ADJUVANTS - THE DEVELOPMENT OF MF59 EMULSION AND POLYMERIC MICROPARTICLES

Vaccines produced by recombinant DNA technology are safer than 'tradit ional' vaccines but they are often poorly immunogenic, requiring adjuv ants to enhance their immunogenicity. Particulate adjuvants of defined dimensions (<5 mu m) have been shown to be effective in enhancing the immunogenicity of 'weak' antigens in animal models. Two novel adjuvan ts that possess significant potential for the develoment of new vaccin es are the MF59 sub-microemulsion and polymeric microparticles. MF59 i s an oil-in-water emulsion and has been shown to be both potent and sa fe in human subjects with several vaccines. Microparticles prepared fr om the biodegradable polymer poly(lactide-co-glycolide) have been show n to enhance immunogenicity when administered by mucosal routes, such as oral and intranasal, and they also possess considerable potential f or the development of single-dose vaccines through the use of controll ed-release technology.