Polymers as immunological adjuvants: An update on recent developments

Polymers are used in several immunological applications, for example in designing new generation vaccines, implantation studies, therapeutics and for the development of animal models that are mimicking human pathological conditions. Polymers can function as attenuators to modulate host immune responses in tissue transplantation, as suppressors to inhibit immune responses against therapeutics or as an adjuvant in the activation of immune responses. Among them, polymers as adjuvants are highly promising and are being developed in the vaccination and autoimmunity fields. As an adjuvant, polymers can efficiently deliver antigens and have the ability to modulate immune responses toward an antigen. Adjuvant properties of the polymers are mainly dependent on their extrinsic and intrinsic properties such as polymer chemistry, format, charge and a fine balance between hydrophobicity and hydrophilicity. Polymers can also be easily coupled with an antigen/immuno-modulator/ligand either physically or chemically. Efficient delivery and protection against degradation of antigens in vivo are some of the advantages of these polymeric adjuvants. Present review focuses on various recent developments in polymeric adjuvants and responsible factors that affect their adjuvant properties.