An ionic liquid-based adjuvant for modulating cellular and humoral immune responses

Vaccination is an important strategy for the prevention of infectious diseases worldwide. Adjuvants can be incorporated in vaccine formulations to enhance the resultant immune response and subsequently confer more robust protection upon natural infection. While adjuvants have exciting potential to improve vaccination, the landscape of materials employed in clinical adjuvants is small and its expansion is needed to facilitate vaccine development against current and future infectious diseases. This study introduces the first ionic liquid (IL) adjuvant comprised of choline and sorbic acid (ChoSorb) to produce an antigen-specific cellular as well as humoral immune response against multiple antigens. The abilities of ChoSorb as a vaccine adjuvant is evaluated and characterized through material analysis, innate immune responses, and adaptive responses to both a model and clinical grade antigen. With the robust immune responses generated by ChoSorb and the accompanying mechanistic insights, this study introduces ILs as a new class of adjuvant materials for future vaccine design.