qs 21

QS-21-Api is an immunostimulatory saponin and a major active component of the natural vaccine adjuvant QS-21, capable of modulating the functions of antigen-presenting cells (APCs) and T cells, thereby inducing both Th2-mediated humoral immunity and Th1-mediated cellular immune responses. In addition, QS-21-Api can activate the NLRP3 inflammasome, promoting the release of caspase-1–dependent cytokines such as IL-1β and IL-18, thereby enhancing Th1 immune responses.

TQL-1055 is a semi-synthetic analog of the saponin adjuvant QS-21, utilized as an adjuvant in preventive vaccines. It demonstrates potent adjuvant activity with influenza antigens and shows good tolerability when combined with an acellular pertussis vaccine (aP), enhancing anti-pertussis toxin (PT) antibody responses in mice and rabbits. TQL-1055 holds promise for research into chronic Hepatitis B.

VSA 1 is a semisynthetic analog of QS-21, serving as a saponin adjuvant. It enhances antigen-specific IgG1 and IgG2a immune responses in BALB/c mice, indicating a mixed Th1/Th2 immune response. VSA 1 significantly increases vaccine efficacy following initial immunization and boosts homologous protection.