An overview of adjuvant formulations and delivery systems

Abstract

Adjuvants may promote immune responses: by recruiting professional antigen-presenting cells (APCs) to the vaccination site, increasing the delivery of antigens to APCs, or by activating APCs to produce cytokines and by triggering T cell responses. Aluminium salts have been effective at promoting protective humoral immunity; however, they are not effective in generating cell-mediated immunity. A number of different approaches have been developed to potentiate immune response and they have been partially successful. Research has been conducted into vaccine delivery systems (VDS); enhancing cross-presentation by targeting antigens to (APCs). Antigen discovery has increased over the past decade, and consequently, it has accelerated vaccine development demanding a new generation of VDS that combines different types of adjuvants into specific formulations with greater activity. The new approaches offer a wide spectrum of opportunities in vaccine research with direct applications in the near future.

On vaccine's adjuvants and autoimmunity: Current evidence and future perspectives

“…These components are defined adjuvants and consist in well-defined molecules and/or formulations [6,8]. Adding an adjuvant to a vaccine antigen leads to practical advantages, including dose sparing and the induction of a more rapid, broader and strong immune response [8][9][10].…”

“…Immune potentiators are often used in combination with the delivery systems and are thought to be able to shift the immune response A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT 5 towards a more Th1 (CD4+) cellular immune response [10]. Approved adjuvants include aluminium salts, oil-in-water emulsions (MF59, AS03 and AF03), virosomes and AS04 [8][9][10].…”

Immunological effects of adjuvants, their mechanisms, and relevance to vaccine safety

“…However, by converting soluble antigen into a particulate form, aluminium adsorption increases antigen uptake by APC, and thus acts as an atigen delivery system. Other adjuvants, classified as delivery systems (liposomes, immune-stimulating complexes, nanoparticles) also function primarily as vehicles to deliver antigens to particular cells or cellular compartments (22).…”

“…Mod ern human vaccines use pre-formed aluminium gels containing sulfate, phosphate or hydroxide salts of aluminum, but composition and higher order structure of different formulations varies considerably (8,22). For some proprietary aluminum salt adjuvants, the full chemical formula and process of formulation are not publicly available.…”

“…Delivery systems can incorporate in their structure some of the previously mentioned adjuvants. They include liposomes, immune-stimulating complexes and nanoparticles (22).…”