Boosting Adjuvant Activity

Abstract

Despite a limited stock approved for clinical application, adjuvants still remain a vital component of vaccines due to their ability to enhance responses against antigens bearing poor immunogenicity. Silva and his colleagues synthesized a novel adjuvant consisting of saponin-bearing detergent-like properties and a monophosphoryl lipid A (MPLA) that serves as a Toll-like receptor 4 agonist, both encapsulated in nanoparticle structures. The novel adjuvant formulation invoked increased antibody and germinal center responses as compared to an assortment of already available adjuvants, in both mice and rhesus macaques post-inoculation of an HIV antigen that had poor immunogenic characteristics. In a mast cell-dependent fashion, increased lymphatic flow was observed with saponin–MPLA nanoparticles. Furthermore, lymph nodes also had an enhanced antigen load, indicating the mechanisms by which saponin consisting of adjuvants improves humoral immune responses. Sci Immunol. 2021 Dec 3;6(66):eabf1152.