An Overview On Chitosan-Based Adjuvant/ Vaccine Delivery Systems

Vaccination is a highly effective and safe method in preventing life-threatening infections in both human and animals. It is based on the principle of activating the immune system and providing protection against infection by administration of the pathogen (antigen) that causes the disease. In general, vaccines can be classified as live-attenuated, inactivated, toxoid vaccines, subunit and highly purified recombinant vaccines. Use of subunit and highly purified vaccines enhances the safety; however, their immunogenicity is relatively low due to their monomeric nature and the absence of other immunostimulatory components. Among the strategies to improve the immunogenicity of subunit vaccines is use of adjuvants and/or delivery systems. Chitosan has been one of the most attractive materials that has been investigated as vaccine adjuvant/delivery system, due to its promising features such as bioadhesivity, biocompatibility, biodegradability, and penetration enhancing activity, as well as bioactive properties (immunostimulatory, anti-inflammatory). In this review, after giving brief information about chitosan and its role in immunization, recent studies on chitosan-based adjuvant/delivery systems will be reviewed in line with the delivery route.