A case-study investigating the physicochemical characteristics that dictate the function of a liposomal adjuvant

The Development of Self-Emulsifying Oil-in-Water Emulsion Adjuvant and an Evaluation of the Impact of Droplet Size on Performance

“…Formulation is an important aspect of adjuvant development as it not only defines the final product and its subsequent stability, but can impact the potency and safety of the final vaccine . Microfluidized emulsion adjuvants gained popularity in vaccines after the success of MF59 and AS03; both are stable formulations with reproducible sizes of around 160 nm .…”

“…Formulation is an important aspect of adjuvant development as it not only defines the final product and its subsequent stability, but can impact the potency and safety of the final vaccine. [17][18][19] Microfluidized emulsion adjuvants gained popularity in vaccines after the success of MF59 and AS03; both are stable formulations with reproducible sizes of around 160 nm. 2,20 The focus of our study was to develop a novel process for manufacturing stable emulsion adjuvants that requires minimal amount of shear with no proprietary equipment.…”

Th1 immune responses can be modulated by varying dimethyldioctadecylammonium and distearoyl-sn-glycero-3-phosphocholine content in liposomal adjuvants

“…The mechanism of DDA : TDB has been investigated, and through a range of studies, the key attributes of the system has been identified as the combination of the ability to codeliver antigen and immunomodulators to APCs (which may result from these systems forming a depot at the injection site), and the ability for the system to stimulate these APCs . Physicochemical factors that control and promote these attributes include the cationic nature of the vesicles and the rigidity of the liposomal bilayer, with vesicle size playing a less important role . Indeed, recent studies suggest that these physicochemical characteristics are key in controlling the ability of the liposomes to promote the formation of an adjuvant/antigen depot at the injection site and that Th1 responses may be supported by depot formation while Th2 responses are not reliant on a vaccine depot, as is the case with alum .…”

“…[22] Physicochemical factors that control and promote these attributes include the cationic nature of the vesicles and the rigidity of the liposomal bilayer, with vesicle size playing a less important role. [23] Indeed, recent studies suggest that these physicochemical characteristics are key in controlling the ability of the liposomes to promote the formation of an adjuvant/antigen depot at the injection site and that Th1 responses may be supported by depot formation while Th2 responses are not reliant on a vaccine depot, as is the case with alum. [24,25] Indeed, recent studies by Kamath et al [26] have shown that synchronisation of DC activation and antigen exposure is required for the induc-tion of Th1/ Th17 responses.…”

Nanoparticle design to induce tumor immunity and challenge the suppressive tumor microenvironment

“…particle size, surface charge, production methods, additional surface modifications) that prevent unbiased conclusion-drawing. Hence, the opinions on carrier-related auto-adjuvancy 8 remain divided: cationic liposomes might induce surface charge density-related DC activation [30][31][32], others show exactly the opposite, pointing towards enhanced adjuvancy of neutral or anionic liposomes [33]. Similar debates arose for PLGA capsules, another commonly investigated antigen-carrier.…”