Innate immune system (via AS01B adjuvant) (AS01B)

The innate immune system, when modulated by the AS01B adjuvant system, acts as a complex biological target to enhance vaccine efficacy (Garçon & Van Mechelen, 2011). AS01B is a liposomal formulation containing two distinct immunostimulants: 3-O-desacyl-4'-monophosphoryl lipid A (MPL) and the saponin QS-21 (Didierlaurent et al., 2017). MPL targets and activates Toll-like receptor 4 (TLR4), while QS-21 is known to activate the NLRP3 inflammasome and promote antigen-presenting cell recruitment (Agnandji et al., 2012). This dual-targeting approach results in a synergistic induction of interferon-gamma (IFN-γ) and the development of robust, long-lived cellular and humoral immunity (Cunningham et al., 2018). AS01B is a critical component of highly successful vaccines, such as Shingrix for herpes zoster and Mosquirix for malaria, where it overcomes the limitations of traditional alum-based adjuvants in eliciting Th1-type responses (Lal et al., 2015). While highly effective, the intense activation of the innate immune system can lead to transient local and systemic reactogenicity, such as injection site pain and fatigue (FDA, 2017). The target 'Innate immune system via adjuvant AS01B' refers to a biological system and a specific adjuvant mechanism rather than a single molecular target (Didierlaurent et al., 2017).

Other names

AS01B Adjuvant SystemAS01 AdjuvantTLR4 and NLRP3 activation pathway

AS01B activates the innate immune system through the synergistic action of MPL (a TLR4 agonist) and QS-21 (an NLRP3 inflammasome activator), leading to enhanced antigen presentation and Th1-biased T-cell responses (Didierlaurent et al., 2017).