HS101 is a vaccine adjuvant and a key component in vaccines. Adjuvants can be divided into immunostimulants and delivery systems. Adjuvants can not only enhance the intensity and durability of immune responses, but also affect the type of immune responses. On the one hand, immunostimulants promote the production of antigen signals and co-stimulatory signals by targeting Toll-like receptors (TLRs) and other pattern recognition receptors (PRRs), leading to the maturation and activation of antigen presenting cells (APCs), thereby enhancing adaptive immune responses; on the other hand, delivery systems are carrier materials that promote antigen delivery by prolonging the bioavailability of loaded antigens and targeting antigens to lymph nodes or APCs. Several common adjuvants include: saponins, TLRs agonists, polysaccharides, nanoparticles, cytokines, and mucosal adjuvants[1][2].
