A Review on Novel Delivery Vehicles for Vaccines Development

The immunogenicity of pure recombinant and synthetic antigens used as vaccines are lesser effective than the vaccines used in previous two decads which were either live, attenuated or killed whole organism. Hence the quality of current vaccines can be improved by either incorporating immunomodulators or adjuvants with novel delivery vehicles like liposomes, immune stimulating complexes (ISCOMs), micro/nanospheres and micro/nanoparticles. Adjuvants are immunological agents that are used in a vaccine to enhance the recipient's immune response to the supplied antigen, thus minimizing the amount of injected foreign material. This review discusses the current status and applictions of various vaccine adjuvants and delivery vehicles developed till date. A detailed discussion on adjuvants and delivery systems with special emphasis on chitosan in vaccine formulation will be done. Applications of chitosan and its derivatives will be reviewed and their proposed mechanisms in the enhancement of immune responses will be discussed.