Oil-in-Water Adjuvant AS03A (AS03A)

AS03A is an oil-in-water emulsion adjuvant system designed to enhance the immune response to vaccine antigens. It is primarily used in influenza vaccines and comprises squalene, DL-α-tocopherol (Vitamin E), and polysorbate 80. The adjuvant enhances both innate and adaptive immunity through increased antigen uptake by antigen-presenting cells, local activation of innate immunity, and enhanced antigen presentation to T cells. Vaccines formulated with AS03A demonstrate enhanced levels of antigen-specific antibodies, improved quality and quantity of adaptive responses, and an antigen-sparing effect.

Other names

Squalene-based adjuvant AS03AAdjuvant System 03AGSK Adjuvant AS03A

Enhances antigen uptake by antigen-presenting cells (APCs), promotes local activation of innate immunity at the injection site, facilitates transport of antigens to draining lymph nodes, leading to higher antibody titers and improved immune memory. Creates a depot effect at the injection site, allowing gradual release of antigen. Recruits APCs such as macrophages and lymphocytes, favoring their accumulation in draining lymph nodes.