c-di-AMP diammonium is a STING agonist, which binds to the transmembrane protein STING thereby activating the TBK3-IRF3 signaling pathway, subsequently triggering the production of type I IFN and TNF. c-di-AMP diammonium is also a bacterial second messenger, which regulates cell growth, survival, and virulence, primarily within Gram-positive bacteria, and also regulates host immune response. c-di-AMP diammonium acts as a potent mucosal adjuvant stimulating both humoral and cellular responses[1][2][3][4].
c-di-AMP diammonium signaling is a central factor in many Gram-positive bacteria regulating cell wall synthesis, potassium ion channels, DNA repair, and biofilm formation. c-di-AMP is also essential for cell growth, survival, and virulence of several well-known human pathogenic bacteria including S. aureus, L. monocytogenes, S. pyogenes, and Mycobacterium spp[1].c-di-AMP diammonium combines with model antigens, such as OVA or β-Gal, acts as a potent mucosal adjuvant stimulating both humoral and cellular responses[4].
[1]. Fahmi T, et al. c-di-AMP: An Essential Molecule in the Signaling Pathways that Regulate the Viability and Virulenceof Gram-Positive Bacteria. Genes (Basel). 2017 Aug 7;8(8).
[2]. Ning H, et al. Recombinant BCG With Bacterial Signaling Molecule Cyclic di-AMP as Endogenous AdjuvantInduces Elevated Immune Responses After Mycobacterium tuberculosis Infection. Front Immunol. 2019 Jul 3;10:1519.
[3]. Ebensen T, et al. The Combination Vaccine Adjuvant System Alum/c-di-AMP Results in Quantitative and QualitativeEnhanced Immune Responses Post Immunization. Front Cell Infect Microbiol. 2019 Feb 19;9:31.
[4]. Sanchez MV, et al. Intranasal delivery of influenza rNP adjuvanted with c-di-AMP induces strong humoral and cellularimmune responses and provides protection against virus challenge. PLoS One. 2014 Aug 20;9(8):e104824.