– Bis-(3′-5′)-cyclic dimeric adenosine monophosphate (c-di-AMP) is a bacterial second messenger implicated in the control of cell wall metabolism, osmotic stress responses and sporulation.
Detection of c-di-AMP by the host cytoplasmic surveillance pathway (CSP) is known to elicit type I IFN responses through a signaling axis that involves STING, TBK1 and IRF3 [1, 2].
Involvement of the helicase DDX41 in the recognition of c-di-AMP has been suggested [3].
Recent studies have also demonstrated that c-di-AMP exerts strong adjuvant activities when delivered by the mucosal route [4, 5].