MF59-modulated innate immune pathways (MF59)

MF59 is a squalene-based oil-in-water emulsion adjuvant used in influenza vaccines, such as Fluad Quadrivalent, to enhance and broaden the immune response, particularly in the elderly population [1]. It functions by creating a local immunocompetent environment at the injection site, which triggers the release of various chemokines (e.g., CCL2, CCL3, CXCL8) and cytokines from resident cells [2]. This signaling leads to the rapid recruitment of innate immune cells, including monocytes, neutrophils, and dendritic cells, which efficiently internalize the vaccine antigens [1,2]. These activated cells then migrate to the draining lymph nodes to promote the differentiation of T follicular helper cells and the production of high-affinity antibodies by B cells [3]. Although MF59 does not directly target specific Toll-like receptors, its activity is dependent on the MyD88 adapter protein and involves the activation of the NLRP3 inflammasome [4]. This orchestrated innate response ultimately results in a more robust, persistent, and cross-reactive adaptive immune protection against influenza viruses [1,3].

Other names

MF59 adjuvant systemMF59-induced immunocompetent environmentInnate immune cells and pathways modulated by MF59 adjuvant in Fluad Quad

MF59 induces a local immunocompetent environment by stimulating chemokine release (CCL2, CCL3, CXCL8), which recruits innate immune cells to the injection site to enhance antigen uptake and transport to lymph nodes [1,2].